Up Andriyivsky uzviz past St Andrew's Church, look for a dense cluster of vendors selling Dynamo Kyiv & other sports paraphernalia on the right. The fenced-off archaeological site behind them covers the foundations of the Desyatynna Church ruins. Prince Volodymyr ordered the church built in 989 and devoted 10% of his income to it, hence the name (desyatyn means 'one-tenth'). The church collapsed under the weight of the people who took refuge on its roof during the Mongol sacking of Kyiv in 1240.
Today the Moscow and Kyiv patriarchates of the Ukrainian Orthodox Church are fighting over the fate of the site - the latter wants to rebuild the church.