Kollegiatstift St. Johann Baptista, Amöneburg

Twenty-five stops in two layers: below, the imperial free city with the Römer, the Kaiserdom, the Paulskirche and Goethe's birthplace; above it the towers – Commerzbank Tower, Messeturm, Main Tower, Eurotower, Silberturm.

The Celts left no single country behind them, only a trail of fortified towns, princely graves and salt-carved landscapes.