I visited the Red Tower of Death on my way back from Karlovy Vary to Prague. I don't recall ever visiting a similarly ugly VHS. The tower is located near the prison and the structure itself has no aesthetic value at all.
The tower is a simple seven-story brick structure. In the 1950s it was used as a sorting plant for uranium ore to be exported to the Soviet Union. The tower was part of a labour camp for political prisoners. The prisoners, mostly opponents of the communist regime, clergymen and airmen who served in the RAF in World War II, had to transport uranium ore to the seventh floor, where the ore was poured down through a system of sieves. From the description it is probably obvious why the tower is called the Tower of Death. The workers were exposed to radiation that was rapidly destroying their health. However, deaths on the death tower itself were rather rare. Sick prisoners were usually transferred to other prisons.
Only the rough structure of the tower remains, with a small exhibition inside commemorating the fate of the prisoners. Visits are only possible with a guide. Visiting is only possible on weekends during the summer holidays (July, August). Do not expect crowds of tourists.