Seventy-five per cent of the food crop varieties we once grew have disappeared from our fields in the last 100 years.

FORBES: The Future of Life On Earth: Part Two Of The Discussion

Along one 20km stretch, recalls Mr Mukerji, the road had disappeared, forcing him to drive through fields.

ECONOMIST: Bihar's remarkable recovery

They would be working the fields and his father would turn around and Albert had disappeared and they would find him "on a stump somewhere speaking to an imaginary crowd, " recalled Donald Lee Hackett, an old family friend.

CNN: Excerpt: 'The Prince of Tennessee: The Rise of Al Gore'

In 1990 Melissa Halstead, an American model turned photographer, disappeared in Amsterdam and 10 years later Paula Fields went missing from the London streets where she worked as a prostitute.

BBC: Killer planted clues in misogynistic artworks