Dominating the scene in Dordrecht is the imposing mass of the 15th-century Grote Kerk (also sometimes called the Onze Lieve Vrouwekerk), whose tower is a good 6 feet off the vertical and whose chancel bends left to symbolize the head of Christ inclining toward his left shoulder. One window pictures the disastrous flood that inundated the city in 1421, and the huge 2,600-pipe organ has a 10-second echo. The 67-bell carillon is claimed to be the largest in Europe. The interior is astonishing in its whiteness, accented by a mahogany sounding board and a bronze screen (which used to be kept brilliantly polished by the local schoolchildren). It was in this church that the Protestant synod met in 1618 to settle the controversy between Arminius and Gomaurus, two professors of theology at Leiden. The outcome was Prince Maurits's choosing for Gomaurus, who believed in a less strict Calvinism. From the church, follow the Voorstraat (on the far side of the canal), with old houses at every turn, to the Groenmarkt, where at No. 31 you'll find the city's oldest house (1550).