The Leaning Tower of Pisa
Sightseeing in Western Europe picture - The construction of this imposing mass started in 1173. The works ceased when it reached its 3rd storey bcos it had started sinking into the ground. It remained thus for 90 years and later completed by Giovanni di Simone, Tommano Simone, crowned the tower with the belfry at half of 14th century. And today, the monument still continues to sink, at about 1 mm each year.