The Aguadilla UFO (2013)
In 2013, a U.S. Homeland Security aircraft filmed on thermal camera, over Puerto Rico, an object skimming the water, diving in and out of the ocean, then apparently splitting in two. An official video, analyzed by independent scientists.
Witnesses
DHS thermal camera
Why it endures
Footage from a federal agency, where the object enters water without slowing.
Official version (contested)
No official explanation. Independent analysis rules out bird, balloon and aircraft.