The trenches were rediscovered at the Ministry of Defence's Browndown site in 2011 First World War practice trenches that were lost beneath heathland for decades have been granted heritage ...

Historian Dan Snow explains to Michael Douglas how the near stalemate of trench warfare in WW1 was relieved by the introduction of tanks, aircraft and shells. We see how protection was provided ...

Following is a transcript of the video. Narrator: The Mariana Trench is the deepest point on Earth. So deep that if you dropped Mount Everest inside, its peak would still be more than a kilometer ...