For someone in search of night life, there can be no better sign than sidewalks that literally hum. Traipsing along Grodzka Street in Krakow one evening, my wife, Shelley, and I thought we were hallucinating. A muffled thumping and a hazy green glow radiated from what appeared to be a glass trapdoor in the sidewalk. The doorways in the area were all dark.

 

 

Turning the corner, we spotted a dark portal at the bottom of a set of stairs. When we opened the door, a wave of the same green haze and bass-heavy house techno washed over us.

 

 

We had stumbled across Prozak, one of Krakow's hottest dance clubs. The touch of hedonism hidden behind the somber facade of Dominikanska Street was a sign of things to come.

 

 

Krakow is like two cities. It is quiet and reserved by day. But by night its basements are crammed with overheated night owls shaking off their stoicism. Jazz oozes from the dark corners of alleys of the Stare Miasto, the Old Town, and cabaret echoes through its Gothic cellars.