Combine two tours to explore both Frankfurt and nearby Heidelberg in one day. Start with a half-day trip to Heidelberg to visit the impressive Heidelberg Castle ruins, Old Town and the Karl Theodor Bridge. Back in Frankfurt, enjoy a 2-hour sightseeing tour by double-decker bus to observe the city's many contrasts. Visit the Romer town hall and Frankfurt Cathedral, walk around the historic city center, marvel at the sleek buildings in Frankfurt's European banking center and much more.