St. Francis Church is located right next to Charles Bridge, on the same plaza as St. Salvator Church of the Klementium, and is accordingly crowded with tourists. What sets St. Francis apart is its magnificent 40 meter high brick aqua blue dome rising above the skyline, a distinctive feature of its Baroque heritage. The current rendition, finished in 1665, was built atop the ruins of the original church of St. Francis of Assisi, built in 1270, and belongs to the Order of the Knights of the Cross with the Red Star―the only such church in Czech. St. Francis features some unusual underground corridors and rooms, featuring artificial stalactites and a chapel, and it also is home to the second-oldest organ in Prague, one which Mozart and Dvorak was rumored to have played upon. Unsurprisingly considering its musical heritage, St. Francis also plays host to some great hour-long classical concerts, though prices lean heavily on the expensive side. Make sure to also check out the former hospital, which has some pieces of the Judith Bridge, the forerunner to Charles Bridge, as well as some original pavement from the 12th century, the oldest in Prague.