Orthodox Church of the Holy Spirit

If you have time for only one church, make it this one. Said to be the only church that remained open during the Soviet period, the main sanctuary has three mummified bodies of Saints Anthony, John, and Eustathios. The trio was executed in 1347 when they angered Algirdas, the pagan Grand Duke of Lithuania, for preaching publicly. Not to be confused with the Dominican Church of the Holy Spirit, this church is only a few steps away from the Gates of Dawn.