Designed by Benjamin Latrobe -- who was working on the U.S. Capitol at the same time -- this neoclassical basilica is considered one of America's most beautiful. A national shrine and historic landmark, it was the first cathedral built in the United States and has been a monument to religious freedom since 1806. Notable visitors have included Mother Teresa and Pope John Paul II, both of whom now have memorials to their visits. A controversial restoration, including the removal of stained glass and uncovering of 24 skylights in the dome, has resulted in a light-drenched sanctuary filled with glittering details. For natives who remember the dark, solemn space, this was a startling revelation and a welcome one. The project also uncovered balconies once reserved for African-American Catholics and cloistered nuns. The undercroft has reopened with a chapel, museum, and crypt. Tours are available Monday through Friday at 9am, 11am, and 1pm, and Sunday at noon. A prayer garden dedicated to Pope John Paul II is around the corner on Charles Street.