The sunken valuables of some of South Asiaâs largest rivers are being retrieved by a daring new breed of amateur diver in Bangladesh. Using a pipe connected to a rudimentary air compressor which is normally used for blowing up tyres the divers can dive to 60m (200ft) in some of the worldâs fast-flowing rivers. The divers collect valuables and artifacts from sunken vessels. The divers known as âkhojiâ or âthose who search for somethingâ can remain underwater for up to one and half hours. From a boat in the middle of a river they tie themselves to a rope and dive in. If they get into trouble, they pull on the rope to indicate an emergency.