World's Greatest Shipwrecks: History Beneath the Waves

Research teams win special permission to investigate two wrecks from World War I lost in the Orkney islands, the warships HMS Hampshire and HMS Vanguard.

Newly discovered vessels from the Spanish Armada and the Dardanelles campaign in Turkey during the First World War, shedding new light on these famous failed invasions.

The tragedy of the Empress of Ireland, Canada's 'Titanic'; and El Faro, which was caught up in a tropical storm in 2015. Both wrecks show how quickly danger can rise up at sea.

The discovery of three German U-boat wrecks, including the world's first ever stealth sub, reveal dramatic stories of 20th-century conflicts at sea.

Investigations off the coast of Scotland reveal one of the greatest acts of defiance in wartime history, dating all the way back to World War I