River Congo: Nation's lifeline
River transport is widely used throughout DR Congo, which has numerous waterways, including the 4,700km (3,000-mile) Congo river.
Many of the boats on the Congo and other rivers are overloaded because of the country's unique geography and political history.
The long time ruler of DR Congo, Mobutu Sese Seko, who held power for nearly four decades until 1997, built hardly any roads or railways in his vast fiefdom.
Cars and trains can be used by armies, and armies on the move can mount a military coup.
So apart from prohibitively expensive air travel, the only way for most people to travel between the west and the east of DR Congo is on ferries and other boats plying the river and its tributaries.
The Congo flows from the mining city of Kisangani in the east, in a great arc through impenetrable jungle, to the capital Kinshasa in the west.
The river is so strategically important that for several years, during the Congolese civil war, boats were banned from it because the authorities in Kinshasa thought it could be used by advancing rebels.
And the location of the capital itself is also determined by a physical aspect of the river.
The waters of the Congo crash into a huge series of rocks at Kinshasa, which is some 400km from the mouth of the river at the Atlantic.
The rocks are known as the Cataracts and are quite immoveable.
Their presence means the Congo river is navigable from Kisangani to Kinshasa but not beyond there to the ocean.