9. Graham Island/Ferdinandea/Ile Julia
As you may be able to tell from its ridiculous number of names, Graham Island, Ferdinandea, or Ile Julia was also claimed by several countries. Located off the coast of Sicily, the island has appeared and disappeared around four or five times, but it was its appearance in July 1831 that sparked a major, four-way diplomatic crisis.
It was first claimed by the British, who planted a flag on it and named it “Graham Island” after Sir James Graham. The Kingdom of the Two Sicilies later planted their flag on it, dubbing it “Ferdinandea.” A month later, the French showed up with a flag of their own to claim ”Ile Julia.” Spain also claimed the island, although they didn’t come up with a name or plant a flag, so nobody took them seriously.
Predictably, the island sank shortly after the French planted their flag, ending its six months in the limelight. However, the island is currently just 8 meters (26 ft) underwater—meaning that it might reappear in the near future. Anticipating another diplomatic row, Italian divers have already gone underwater and planted a flag on it.