Lake Victoria is the largest tropical lake in the world and is the source of the largest branch of the Nile River. It is a biological hotspot with great biodiversity. It is in the western part of Africa's Great Rift Valley and is subject to territorial administration by Tanzania, Uganda and Kenya. It has more than 3,000 islands, many of which are inhabited. These include the Ssese Islands in Uganda, a large group of islands in the northwest of the Lake that are becoming a popular destination for tourists. Lake Victoria plays a vital role in supporting the millions of people living around its shores, in one of the most densely populated regions on earth.