The Washa Mikael Church is a few kilometres east of Addis Ababa's town centre. Though local priests date it back to the 3rd century AD, it most probably dates back to the 12th century. If you’re mad and not planning to visit the churches at Lalibela or Tigray in the north, this is definitely worth a peek as an example of the extraordinary rock-hewn architecture that Ethiopia is so famous for. Unfortunately, from July to October it’s usually flooded with rainwater.
The church is tricky to find, so ask locals en route.
Finally, a word of warning: a number of tourists have been mugged on the road up to the church, so go with a friend or two.