Basilica of the National Shrine of the Immaculate Conception

The largest Catholic house of worship in North America can host 6000 worshippers (Some might say that’s when the building is at critical mass. Get it? Sorry.) This is an enormous, impressive, but somehow unimposing edifice, more Byzantine than Vatican in its aesthetic. Outlaid with some 75,000 sq ft of mosaic work and a crypt modeled after early Christian catacombs, the (literal) crowning glory is a dome that could have been lifted off the Hagia Sophia in Istanbul. The Marian shrine sports an eclectic mix of Romanesque and Byzantine motifs, all anchored by a 329ft minaret-shaped campanile. Downstairs, the original eastern-style crypt church has low, mosaic-covered vaulted ceilings lit by votives and chandeliers. Upstairs, the main sanctuary is lined with elaborate saints’ chapels, lit by rose windows and fronted by a dazzling mosaic of a stern Christ.