The area is beautiful but desolate, with amazing beaches. She'll first go by Ghoubbet al-Kharab, an inlet to the Red Sea. And yes, that's a volcano.
From the official Djibouti toursism site
Lac Assal is a natural curiosity of great beauty, in a framework of volcanos and black lava, 155 m below sea level. This is the lowest point of the African continent. There is no outflow from the lake and, due to high evaporation, the salinity level of its waters is ten times that of the sea, making it the most saline in the world after Don Juan Pond in Antarctica. Lake Assal is a hallucinating show, with in the background the black lava from volcanoes that accentuates the contrast of the dazzling Turquoise of the salty hot water, the azure of the sky is hardly able to temper. In addition to tourists, we often encounter trucks carrying salt from the Lake to the Ethiopian Highlands under the amused gaze of sellers of souvenirs. Attention to the hot springs, water temperature can be above 40 Celcius. The Government of Djibouti has initiated a proposal with UNESCO to declare the Lake Assal zone and the Ardoukoba volcano as a World Heritage Site.
Hmm. The 2nd salty-est in the world, but there's one in Antarctica that is saltier? Please don't mention that to Janet!