The most popular route are on the left bank of the Vistula, from Młociny to Powsin. Bikes can be ridden in the Kampinos Forest and the Kabaty Forest. A well developed network of bike trails can be found in Ursynów, Bemowo and Białołęka. The Vistula can be easily crossed on a bike across Świętokrzyski and Siekierkowski bridges. All those interested in discovering Warsaw on two wheels but not owning a bicycle can use rentals.
The Warsaw Critical Mass, one of the largest events of this type, starts out on every last Friday of the month at 6 pm on Zamkowy Square, regardless of the weather. It is organized by volunteers and aims at uniting all those who care about improving the situation of Warsaw bikers.
Source (map): Warsaw's Cycling Report 2010, Warsaw City Hall's Department of Transport and Road / Department of Architecture and Town Planning