The Old Town Bridge Tower is the gateway to Charles Bridge. The tower was built in the 14th century. famous architect Peter Parlerzh, its construction lasted 23 years. The tower is a three-storey building with a jagged top and a high hipped roof. The lower floor of the tower is formed by a gate with a Gothic arch opening, and the passageway is decorated with frescoes. On the second floor of the Old Town Bridge Tower, there was once a guardhouse for the control of the lattice, the third floor served as a debtor's prison for debtors from wealthy families, and at the very top, at a height of 47 m, there is now an observation deck on Charles Bridge and Hradcany. The tower is decorated with symbols, coats of arms, sculptures and statues of saints and kings Charles IV and Wenceslas IV.
The rich decor of the façade testifies to the double purpose of the tower: it is not only a defensive building, but also a kind of triumphal arch on the royal road to Prague Castle.