The cathedral of Tournai is the oldest, the most vast, and decidedly the most imposing religious edifice in Belgium. Its five great towers dominate the entire city and are visible for miles across the surrounding plains. The oldest portions of the present structure date from about 880, when the inhabitants of Tournai returned after the invasion of the Norsemen. The side porches of the naves belong to this earliest period. In 1054 a fire destroyed the upper part of the cathedral and it was shortly after this that the towers were built. There were originally seven of these, the one in the centre being a gigantic square structure rising above all the others. The group as it then stood was without a rival in Europe, but the two towers to the east of the central one were removed with the ancient choir and the height of the central tower reduced. In their present form, however, the towers compose a magnificent assemblage. [Illustration: GENERAL VIEW OF TOURNAI AND THE FIVE-TOWERED CATHEDRAL.] The four outer towers, which surround the now much shorter central one, are two hundred and seventy-two feet high, and, although apparently alike at the first glance, are not entirely so--a circumstance that enhances rather than detracts from the picturesqueness of the group. Placed at the crossing of the nave and the transept these towers, from without, suggest the fantastic idea that instead of one there are two cathedrals, each facing the other, and with the central tower uniting them. In reality, the edifice is large enough to make two cathedrals and more, the interior being four hundred and twenty-six feet in length and two hundred and twenty feet in width across the transept. Built at different epochs, this imposing edifice constitutes a veritable history in stone of the development of mediæval architecture. The nave was completed in 1070 and the transept in the eleventh and twelfth centuries. Both are in the Romanesque style, while the choir--originally Romanesque--was rebuilt in 1242-1325 in the early Gothic style. It is both longer and almost fifty feet higher than the older nave--a fact that leads the observer looking at the structure from without to mistake it for the nave itself. In addition to the main edifice there is a small parish chapel built against the north side of the cathedral, a Gothic edifice dating from 1516-1518, while attached to it by a passage over a picturesque arch called _Le fausseporte_ is the Bishop's palace. Here there is another chapel, the Chapel of the Bishops, dating from the twelfth century.