Lake Tana is the largest lake in Ethiopia (3,000km square) is the source of the famed Blue Nile which starts its long journey to Khartoun, and the Mediterranean. The 37 islands that are scattered about the surface of the lake shelter fascinating churches and monasteries, some of which have histories dating back to the 13th century. Kebran Gebriel is the principal monastery visited by male tourist from Bahar Dar, with its impressive, cathedral like building first built at the end of the 17th century. However, it should be noted that most of religious houses are open to women. Bird lovers will not miss Fasilidas Island. A sail or cruise on a Lake Tana is one of the most pleasant excursion for visitors to this region, particularly in the heat of summer.