Got the tip from a friend who's been living in Warsaw, didn't know what to expect but were pleasantly surprised. Our guide Michal took us for a 2,5 hour tour around the old and new town of Warsaw, where he told us not only about these parts of Warsaw but also about the history of Poland. Even in the freezing weather he kept us intrigued with humor (and Vodka!), and we gladly completed the whole tour. (You are free to join and leave at any point). Can absolutely recommend this tour, dress warm and bring a camera.