Basilica of the National Shrine of the Immaculate Conception

The largest Catholic church in North America and one of the ten largest churches in the world, standing next to the Catholic University of America in the Brookland neighbourhood of northeast Washington. Built between 1920 and 1959 in a Byzantine-Romanesque style that deliberately avoids the Gothic of the National Cathedral, it is a riot of colour inside: over 80 chapels and oratories donated by ethnic Catholic communities from around the world, and more than 7,000 square metres of mosaic, including the Christ in Majesty apse and the Trinity Dome, finished in 2017 as the last major element of the interior. The 100 m Knights Tower and the blue and gold main dome are visible from much of the city. Three popes have visited, and Mother Teresa, Pope Francis and Pope John Paul II celebrated Mass here.

Practical: Free entry, open daily from early morning to evening; the Crypt Church on the lower level is the older and more intimate space. Free guided tours run several times a day. Large free parking lot on site, and Brookland-CUA metro station is a five minute walk. Allow 45 minutes to an hour; combines well with the National Cathedral for a contrast of America's two great 20th century churches, about 20 minutes apart by car.