Which African kingdom's rock-hewn churches stand at Lalibela?

Ethiopia, and the churches are not built - they are excavated. Eleven of them were cut downward out of solid volcanic rock in the twelfth and thirteenth centuries, so a builder began with a hillside, carved a trench to isolate a block, then hollowed the interior out through the windows and doors. There is no foundation and no joint anywhere, because each church is one continuous piece of the mountain.

The largest, Bete Medhane Alem, is around 33 metres long and 11 high with 36 pillars, all of it subtractive. Bete Giyorgis is a cross in plan, cut into a pit, invisible until you stand at the edge. Tunnels and trenches connect them, and the whole complex was conceived as a New Jerusalem after Saladin's capture of the original made pilgrimage impossible.

They are still working churches, which is the part visitors are least prepared for - priests, services, pilgrims and centuries of candle soot, rather than a monument. Their condition is now a serious problem: the rock is porous and weathering, and UNESCO-funded shelters erected over several of them in 2008 as a temporary measure are still there, widely disliked, and themselves deteriorating.