Daugavpils has a remarkable density of religious buildings packed into its old town, reflecting centuries of overlapping communities. Within a few blocks you'll find Russian Orthodox, Roman Catholic, Lutheran, and Old Believer congregations — the Old Believers being a particularly significant presence in Latgale, having settled here after fleeing persecution in Russia in the 17th century. The Boris and Gleb Cathedral is the most striking Orthodox church, with its blue domes visible from much of the centre. The concentration of different faiths in a single neighbourhood is one of the more quietly fascinating things about Daugavpils.