Agen Cathedral

You're standing at Agen Cathedral, dedicated to Saint Caprasius. Start with the bell tower, in the corner between the nave and the south transept. It looks medieval, but it only went up in 1835, replacing an old wooden tower. Here's the fun part: it mixes three Gothic styles, stacked in reverse order. As your eye climbs, you travel backwards in time. A tower that tells history upside down.