The old KGB headquarters in the Lithuanian capital, Vilnius, is a sinister place, full of ghosts. It is a solid 19th-century neoclassical building with walls thick enough to have muffled the screams of those under interrogation. The cells in the basement are as cold and damp as they were in Soviet times and there are stone steps down to an airless, claustrophobic chamber where prisoners were executed, a thousand of them, the wall still pock-marked with bullet holes.