In pictures: Underground children

Across from the main post office, there is a sewage drain. It draws little attention.

Thousands of people walk across its steel bars every day without giving it a second thought. This is good for Mohammed and his friends. They do not want their home to be discovered.

The space is not more than half a metre high, and though it is five or six metres long, only one small portion is covered and unexposed.

When it rains, the boys huddle together among the rubbish and waste.