A well-known structure that's withstood the passage of time, don't miss Siebers Tower. It's a popular attraction for history buffs and regular sightseers alike.
You'll be spoiled for sightseeing choice in Rothenburg Old Town. Siebers Tower is a great place to begin here, but there are lots of other interesting spots to explore. Rothenburg Town Hall, Rothenburg Town Walls, and Rothenburg Plonlein are not far from the historic construction and will round out your day nicely.