What On Earth?

Discover a massive tsunami hundreds of feet high that never touches land and an image from space may have revealed the location of the Garden of Eden. (S1, ep 1)

Discover an island the size of Manhattan that vanishes without a trace and a lost city in the heart of the Amazonian jungle. (S1, ep 2)

First seen from space in 1965, the Eye of the Sahara is a beautiful 25-mile structure, but how it formed remains a mystery. (S1, ep 3)

NASA astronaut Mike Barratt describes photographing a strange ring in the ice on the world's oldest lake from the International Space Station. (S1, ep 4)

A possible smoke screen over North Korea worries military analysts while an amateur archaeologist makes an extraordinary discovery. (S1, ep 4)

A strange, eerily colourful ocean seen from space conceals a terrible secret - its waters are killing all sea life in and around it. What is causing this dead zone? (S6, ep 18)

A mysterious explosion shakes a German village. When the culprit is identified as a dormant Nazi bomb, it triggers a hunt to rid a town of these deadly relics of World War II. (S6, ep 19)

Sometimes, the greatest mysteries revealed by satellites aren't what you can see, but what you can't. Why does a town appear on maps for decades, yet it is invisible from space? (S6, ep 20)