Housed in a former convent, the StB Holding Cells were used by the StB (Communist secret police) to interrogate and hold political prisoners. Havel stayed in room P6 during one of his frequent visits between 1977 and 1989. After the revolution, the holding cells became a spartan but popular hostel with months-long waiting lists of tourists who wanted to stay in Havel's hovel. It's now a luxury hotel.