Tis Issat is the Smoke of the Nile - the falls of the Blue Nile in Ethiopia (map). The Blue Nile, arising in Lake Tana, provides most of the water to the Nile proper.
Here's a better photo of the falls.
You can learn a lot about 19th C. Ethiopia (Abyssinia) in Flashman on the March (he survives a tumble down the falls - and then a tumble with an obese Queen). The subject comes up today because, after church yesterday, friends were discussing their upcoming mission trip to Ethiopia and I regret that I cannot join their group.
On the other hand, maybe Ethiopia ought to be sending some missions to the USA and Europe. The Ethiopian Orthodox Church (previously the Coptic Orthodox Church) has been around since about 300, and has taken its own path. Note the outfits of the Deacons.
I would love to see that country.