jonas james has been doing this for twenty years. it's grueling work. he has to stay underwater for up to four minutes to fill his bucket with sand from the seabed. the work is dangerous and hard on the health. but as a guest worker from neighboring benin, james can't pick and choose his jobs. >> i try to save a little. lagos is very expensive, and thirty euros is not much pay, so i can only go see my family in benin once a year. i stay there for two weeks, and then i have to come back. >> the sand divers have formed a kind of brotherhood, but they don't all earn an equal wage for their work. a boat owner points out the danger involved. >> i have two boat. the other boat belongs to our people, where we come from. we have a leader, who has the boat and employs the workers to bring up the sand. at times, if they're working hard, somebody can go deep down without coming back. >> lagos' center is wedged between the atlantic and the lagoon. the only land available for building has to be dredged up from the sea, and that takes sand -- lots of it. and that's t