248 F.3d 1051 (11th Cir. 2001)
Lionel BEKIER, In the matter of Jonathan Bekier, infant, Plaintiff-Appellee,v.Bettina Srour BEKIER, In the matter of Jonathan Bekier, infant, Defendant- Appellant.
Nos. 99-13347, 99-13944.
United States Court of Appeals, Eleventh Circuit.
April 16, 2001.April 26, 2001.

Appeals from the United States District Court for the Southern District of  Florida. (No. 99-08565-CV-DTKH), Daniel T.K. Hurley, Judge.
Before EDMONDSON and MARCUS, Circuit Judges, and RESTANI*, Judge.
EDMONDSON, Circuit Judge:


1
Bettina Srour Bekier asks this court to determine whether a child born in  France, removed to Israel by his father, and then removed to France and the  United States by his mother should be returned to Israel with his father. The  Hague Convention on the Civil Aspects of International Child Abduction, Oct. 25,  1980, T.I.A.S. No. 11670, 19 I.L.M. 1501 codified at 42 U.S.C.  11601 et seq,  [hereinafter "Hague Convention"], would govern this inquiry.1 But first we must  be sure that we have a live case or controversy before us. Because we conclude  that the case is moot, we dismiss the appeal and vacate the district court's  judgment.

I.

2
Lionel Bekier and Bettina Srour Bekier married in France in 1990 and gave birth  there to their only child, Jonathan. When the couple divorced in 1994, the  French divorce decree awarded temporary physical custody to the father,  visitation and lodging rights to the mother, and joint legal custody to both  parents.


3
While the final custody determination was pending in France, Ms. Bekier gave  written permission for Mr. Bekier and the child to travel to Israel "to make  their aliyah as temporary residents." Mr. Bekier and his son arrived in Israel  in July 1994. Although Mr. Bekier's passport permitted entry only until November  1994, Mr. Bekier began procedures to qualify for permanent residency in Israel;  and he registered Jonathan for kindergarten.


4
Ms. Bekier visited the father and child in Israel and agreed to postpone a  French custody hearing. Mr. Bekier filed a claim for custody of Jonathan in the  Rabbinical Court of Tel Aviv. The Israeli court issued a "No Exit Order" to  prevent removal of Jonathan from Israel. The court also awarded custody to Mr.  Bekier and granted Ms. Bekier visitation rights. Thus Mr. Bekier has permanent  custody rights in Israel; the issue of permanent custody remains unresolved in  France.


5
On 2 March 1995, Ms. Bekier and Jonathan left Israel for France, eventually  relocating to New York and then South Florida. Mr. Bekier was unaware of  Jonathan's location until 1999, when a private investigation service located Ms.  Bekier and Jonathan.


6
In 1998, Mr. Bekier filed a petition under the Hague Convention in France.  French authorities referred the petition to Israel, determining that Israel had  proper jurisdiction over the petition. When Mr. Bekier finally learned that  Jonathan was in Florida, he-in the Southern District of Florida-filed a petition  for return of the child under the Hague Convention and 42 U.S.C.  11601.


7
The district court concluded that Jonathan had been wrongfully removed from his  habitual residence of Israel and ordered that the child be given to Mr. Bekier  for return to Israel. On 26 August 1999, the court issued a conditional stay,  ordering the child to remain in Dade or Broward counties if Ms. Bekier filed an  appeal within ten days. The stay also required Ms. Bekier to post a $100,000  bond. Ms. Bekier filed her notice of appeal within the ten-day limit, but she  posted no bond. Sometime in mid-October, Mr. Bekier returned to Israel with his  son, where they are currently residing.2

II.

8
The Hague Convention determines which contracting state has jurisdiction to  resolve the underlying custody dispute. The purposes of the Convention are "to  secure the prompt return of children wrongfully removed to or retained in any  Contracting State" and "to ensure that rights of custody and of access under the  law of one Contracting State are effectively respected in the other Contracting  States." Hague Convention, art. 1. But the Convention sets no guidelines or  requirements for determining custody; that determination remains subject to the  laws of the proper forum state as determined by the Convention. The Convention  rests on the premise that each member state is adequately and equally capable of  determining which state should resolve custody disputes.

III.

9
Because we are a court of limited jurisdiction, we must first consider whether  we have jurisdiction to review this appeal. A person seeking return of his  child, under the Hague Convention, may petition in any court authorized to  exercise jurisdiction "in the place where the child is located at the time the  petition is filed." 42 U.S.C.  11603(b); see also Lops v. Lops, 140 F.3d 927,  936 (11th Cir.1998). The district court initially had jurisdiction over this  dispute because, at the time Mr. Bekier filed his petition, Jonathan was located  in the Southern District of Florida. But after the district court ordered the  child to be returned to Mr. Bekier, Mr. Bekier returned to Israel with his son.  This exit raises the question of whether this case is moot.3 We conclude that  this case is moot.


10
A case is moot if no case or controversy exists for us to resolve: "when the  issues presented are no longer 'live' or the parties lack a legally cognizable  interest in the outcome." Reich v. Occupational Safety and Health Review Comm.,  102 F.3d 1200, 1201 (11th Cir.1997) (quoting Powell v. McCormack, 395 U.S. 486,  89 S.Ct. 1944, 1950-51, 23 L.Ed.2d 491 (1969)). We have no authority "to give  opinions on moot questions or abstract propositions, or to declare principles or  rules of law which cannot affect the matter in issue in the case before [us]."  Church of Scientology v. United States, 506 U.S. 9, 113 S.Ct. 447, 449, 121  L.Ed.2d 313 (1992)(internal citations and quotations omitted). If an event  occurs during the pendency of an appeal "that makes it impossible for this court  to grant any effectual relief whatever to a prevailing party, the appeal must be  dismissed."4 Id. at 449.


11
Applying these general principles of mootness, we turn to the facts of this  case. Mr. Bekier petitioned to the district court for the return of Jonathan to  his alleged habitual residence in Israel. The magistrate judge's Report and  Recommendation (R&R)-applying the Hague Convention-recommended that the district  court grant Mr. Bekier's petition for return of the child to Israel. The  district court "adopted, affirmed, and implemented" the R&R in its entirety and  ordered that Jonathan be given to Mr. Bekier for return to Israel. Jonathan and  Mr. Bekier have since returned to Israel. Thus, Mr. Bekier has achieved the  relief he sought in his Hague Convention petition. See Westmoreland v. National  Transp. Safety Bd., 833 F.2d 1461, 1463 (11th Cir.1987) (dismissing appeal as  moot when relief initially sought [reinstating plaintiff's pilot certificate]  already occurred: "there is no need for the Court to grant that relief.").


12
Ms. Bekier now appeals, but what relief we can offer her or what "legally  cognizable interest [she has] in the outcome [of this appeal]" is not clear.  Wakefield v. Church of Scientology of Cal., 938 F.2d 1226, 1229 (11th Cir.1991)  (internal citations omitted). In her merits brief to this court, Ms. Bekier asks  us either to reverse the district court's decision or to remand the case for a  further evidentiary hearing based on allegedly newly procured evidence. But a  reversal of the district court's order will provide Ms. Bekier with no actual  affirmative relief. Jonathan has already returned to Israel. See B&B Chem. Co.,  Inc. v. United States E.P.A., 806 F.2d 987, 989 (11th Cir.1986) (dismissing  challenge to executing warrant as moot because warrant had already been  executed). Ms. Bekier's potential remedies now lie in the Israeli courts. Any  words by us would be merely advisory.


13
We suppose that we would have jurisdiction if Jonathan had remained in the  United States, either under court order or for other reasons. We have previously  recognized that, while a party need not necessarily seek a stay of a lower  court's judgment to protect that party's right to appeal, "the consequence of  failing to obtain a stay is that the prevailing party may treat the judgment of  the district court as final." In re Sewanee Land, Coal & Cattle, Inc., 735 F.2d  1294, 1295 (11th Cir.1984) (internal citations and quotation omitted). We  continued:


14
[I]n the absence of a stay, action of a character which cannot be reversed by    the court of appeals may be taken in reliance on the lower court's decree. As    a result, the court of appeals may become powerless to grant the relief    requested by the appellant. Under such circumstances the appeal will be    dismissed as moot.


15
Id. In Sewanee Land, a bankruptcy case, we dismissed the appeal as moot because  the debtor had failed to obtain a stay pending appeal and the property in  dispute had already been sold to creditors at foreclosure. Id. The court was  thus powerless to grant the relief requested by the appellant.


16
When Jonathan returned to Israel with his father, we became powerless to grant  the relief requested by Ms. Bekier. And so we must dismiss this appeal. See  Brown v. Orange County Dep't of Soc. Serv., No. 94-56274 (9th Cir. July 1, 1996)  (unpublished) (dismissing as moot appeal under Hague Convention because child  had returned to Austria); Mahmoud v. Mahmoud, No. 96-4165 (E.D.N.Y. Jan.24,  1997) (unpublished) (dismissing as moot Hague Convention petition because child  had returned to England); see also Hague Convention, art. 12 ("Where the  judicial or administrative authority in the requested State has reason to  believe that the child has been taken to another State, it may stay the  proceedings or dismiss the application for the return of the child.").


17
Ms. Bekier argues that "to dismiss this appeal for mootness defeats the spirit  and the explicit intention of the Hague Convention."5 And we understand that our  decision to some degree conflicts with the purposes of the Convention: to  prevent parents from fleeing jurisdictions to find a more favorable judicial  forum and to return children to their habitual residence in a timely fashion.  But the United States Courts are restricted by the jurisdictional doctrine of  mootness. Given our duty to respect the limits of our judicial authority, we  will not create a "live" case or controversy in an effort to promote the spirit  of the convention. See Walsh v. Walsh, 221 F.3d 204, 214 (1st Cir.2000)  ("[N]either the Convention nor the U.S. implementing legislation restricts the  appellate process.").


18
"Where a case becomes moot after the district court enters judgment but before  the appellate court has issued a decision, the appellate court must dismiss the  appeal, vacate the district court's judgment, and remand with instructions to  dismiss as moot." United States v. Ghandtchi, 705 F.2d 1315, 1316 (11th  Cir.1983); see also United States v. Munsingwear, Inc., 340 U.S. 36, 71 S.Ct.  104, 107, 95 L.Ed. 36 (1950) ("That procedure clears the path for future  relitigation of the issues between the parties and eliminates a judgment, review  of which was prevented through happenstance."). While some exceptions to this  general rule exist, the Supreme Court has noted that "[a] party who seeks review  of the merits of an adverse ruling [ ] ought not in fairness be forced to  acquiesce in the judgment ... when mootness results from unilateral action of  the party who prevailed below." U.S. Bancorp Mortgage Co. v. Bonner Mall P'ship,  513 U.S. 18, 115 S.Ct. 386, 391-92, 130 L.Ed.2d 233 (1994). Mr. Bekier's removal  of Jonathan from the United States to Israel caused this appeal to become moot.  Thus, because we determine that the case is moot, we must DISMISS this appeal  and instruct the district court to VACATE its order and DISMISS the case.6


19
Appeal DISMISSED.


20
Case REMANDED for dismissal.



NOTES:


*
  Honorable Jane A. Restani, Judge, United States Court of International Trade,  sitting by designation.


1
  The United States and Israel are both signatories to the Hague Convention. See  Hague Conference on Private International Law: Report of the Second Special  Commission Meeting to Review the Operation of the Hague Convention on the Civil  Aspects of International Child Abduction, 33 I.L.M. 225, 225 (1994).


2
  Some confusion existed surrounding the temporary stay order. The stay had not  been lifted when Mr. Bekier left the United States with Jonathan. But the  district court later concluded that the permanent stay order would not go into  effect until Ms. Bekier filed an appeal and posted the $100,000 bond and that  Ms. Bekier's failure to pay the bond caused the temporary stay to expire after  ten days. The district court concluded that Mr. Bekier was "free to leave after  the ten (10) day period ended." That Mr. Bekier left without willfully violating  a district court order is material.


3
  Both parties argue that the appeal is not moot. Nonetheless, we must "consider  issues of mootness sua sponte and, absent an applicable exception to the  mootness doctrine, [we must] dismiss any appeal that no longer presents a viable  case or controversy." Pacific Ins. Co. v. General Development Corp., 28 F.3d  1093, 1096 (11th Cir.1994).


4
  Three exceptions to the mootness doctrine exist: (1) if the issue is capable of  repetition, yet evades review; (2) if the appellant has taken all necessary  steps to perfect the appeal and to preserve the status quo; and (3) if the  district court's order will have possible collateral legal consequences.  Wakefield v. Church of Scientology, 938 F.2d 1226, 1230 (11th Cir.1991). Neither  party argues that any of these exceptions apply, and we see no obvious  application of any exception here.


5
  Ms. Bekier points to Friedrich v. Friedrich, 78 F.3d 1060 (6th Cir.1996), where  the Sixth Circuit noted that "staying the return of a child in an action under  the [Hague] Convention should hardly be a matter of course. The aim of the  Convention is to secure prompt return of the child to the correct jurisdiction,  and any unnecessary delay renders the subsequent return more difficult for the  child, and subsequent adjudication more difficult for the foreign court." Id. at  1063 n. 1. But see Walsh v. Walsh, 221 F.3d 204, 213-14 (1st Cir.2000)  (concluding that issuance of stay pending appeal of Hague Convention petition  was no abuse of discretion). But this dicta by the Sixth Circuit does not  address the court's jurisdiction or the possibility that the child's exit from  the United States pending appeal, even if the exit is made with the district  court's permission, renders the appeal moot.


6
  We also dismiss as moot all pending motions and related appeals, including  appeal no. 99-13944.


