Nat Geo HD

The story of HMS Upholder and HMS Unbeaten - two British submarines who unknowingly took aim at each other while hunting Italian supply ships. (S2, ep 4) 7+.

Nat Geo Explorer Ben Horton races through Guizhou chasing epic waterfalls, adrenaline thrills and unforgettable local culture. (S2, ep 1) 7+.

Experts head to the bottom of the Pacific Ocean in search of famous wrecks from World War II, including the ship that delivered the Hiroshima bomb. 7+.

Archaeologists explore the final days of the pharaohs, revealing how power struggles influenced the fate of one of the world's greatest civilisations. (S6, 6 of 8) 7+.

Italy's Morandi Bridge was an engineering marvel - until it was a national embarrassment. Plus, as impressive as billboards are, they can really come down hard. (S1, ep 8) 7+.

Barry has long hoped to restore his 1984 Audi UR Quattro. Health issues, however, have left him sapped of energy, so Tim and Fuzz step in to help. (S3, ep 2) 7+.

During monsoon season at a treacherous tabletop runway in India, the crew of Flight 1344 runs off the tarmac and their Boeing 737-800 plunges into a gorge. (9 of 10) 7+.

Uncover the truth as trials unfold, hidden reactor dangers emerge and decades later Chernobyl's exclusion zone becomes a war zone. (4 of 4) 7+.

On 3 April 1974, almost 150 tornadoes touched down in 13 US states. Why did so many deadly twisters form in just one day, and can a repeat be prevented? 7+.

Root for a comeback as Tim and Fuzz race to save a rusted Alfa Romeo and restore a dream stolen by heartbreak and time. (S14, ep 7) 7+.

In August 1944, an American artillery observer and his radio is all that stands between the French town of Mortain and capture by the Nazis. 7+.

Investigators struggle to access the site where a Santa Barbara Airlines Flight crashed in 2008. Can they gather enough evidence to prove what went wrong? 7+.

The plug gets pulled on Scotland's famous loch as experts search for the truth about Nessie. But as the waters drain, more than a monster is revealed..

Go on a journey through one of the most iconic castles in the world as it undergoes a complete restoration. 7+.

Brace for disaster as highways fall, bridges collapse and buildings crumble in a global tour of shocking engineering failures. (S3, ep 2) 7+.

Clues point to a mechanical problem when a Continental Airlines flight crashes. But then, investigators find the true culprit in the Rocky Mountains.