Form follows function, even in church architecture. Louis Sullivan was retained by St. Vladimir's Russian Orthodox parish to design a suitable hall of worship. What he came up with was a unique approach to traditional Byzantine design. The elaborate interior of Holy Trinity Russian Orthodox Cathedral comes as a surprise after one views the simple exterior. A richly ornamented altar looks out at a number of icons and paintings. The interior is based on St. Vladimir's Cathedral in Kiev. With no pews, worshipers kneel and stand to hear services that are performed in both Old Slavic and English.