The Nile Delta from Gemini 4, 1965.

The American Gemini missions of the mid-1960s brought back stunning colour photographs of the blue planet from orbit. This one shows the Nile Delta from 135 miles up. Astronauts were struck by the way that national boundaries were invisible from space, which made the wars going on below seem futile. ‘Touristy shots’ like these were at first a low priority for NASA engineers – ‘Those are just pictures of the Earth’ commented one – but after this NASA came to recognise the value of Earth photography although it continued to struggle for mission time. (NASA)