No one should visit Kyiv without seeing the Kievo-Percherska Lavra (Києво-Печерська лавра), the Monestery of the Caves, founded in 1015:
We didn't go into the caves (and I couldn't have photographed them anyway), but we did explore the grounds. (For what it's worth, Lonely Planet recommends getting there early and going straight to the caves. Next time.)
Complete view of the main entrance to the upper Lavra:
Dormition Cathedral: