The Round Tower, Glendalough. The famous Round Tower is about 34 metres high and is 16 metres in circumference at the base. It is still in near perfect condition even though it is almost 1,000 years old! The tower originally had six wooden floors and was connected by ladders. The four stories above the entrance are beautifully lit by a tiny window, while the top story has four windows. The tapering roof was redone in 1876 using the stones that were originally used.