Peter the Great was designing the city as another Amsterdam and Venice, with canals instead of streets and citizens skillful in sailing.
[citation needed] Today, there are more 342 bridges over canals and rivers of various sizes, styles and constructions, built at different periods.
Thanks to the intricate web of canals, Saint Petersburg is often called the "Venice of the North" which is a popular poetic name for the northern capital.
Every night during the navigation period from April to November, 22 bridges across Neva and main canals are drawn to let ships pass in and out of the Baltic Sea into the Volga-Baltic waterway system.
A calculated schedule with precise time of consecutive opening and closing for each bridge is maintained to guarantee passage of cargo ships and tankers at a precisely controlled speed, in order to have at least one bridge at a time staying connected to ensure passage for firefighters, police, ambulances and other ground transportation.