Pheasant Island

Pheasant Island (, , ) is an uninhabited river island in the Bidasoa river, located between France and Spain, whose administration alternates between both nations.
The island is a condominium established by the Treaty of the Pyrenees in 1659, under joint sovereignty of Spain and France, and for alternating periods of six months is officially under the governance of the naval commanders of San Sebastián, Spain (1 February – 31 July) and of Bayonne, France (1 August – 31 January); in effect it is administered respectively by Irun (in Gipuzkoa, Spain) and Hendaye (in the Pyrénées-Atlantiques, France).
Geography.
, the island is approximately long and wide, and is eroding.
History.
The most important historical event to have taken place on the island was the signing of the Treaty of the Pyrenees. This was the climax to a series of 24 conferences held between Luis de Haro, a Grandee of Spain and Cardinal Mazarin, Chief Minister of France, in 1659 following the end of the Thirty Years' War. A monolith was built in the centre of the island to commemorate the meeting.
The island has also been used for several other royal meetings:
Access.
The island can sometimes be reached from the Spanish side at low tide. It is uninhabited, and access is forbidden except very occasionally on heritage open days. Other than that, employees of the municipal government of Irun or Hendaye may access the island once every six months for cleaning and gardening, and members of the Naval Commands of San Sebastián (Spain) and Bayonne (France), responsible for monitoring the island, will land on it every five days.