Famous Blue Bridge over the Moyka River is the widest bridge in the world. It is 97.3 meters in width. The bridge, standing in front of the Mariinsky Palace (where a city council is housed) is an important part of the St. Isaac's square architectural ensemble.
This unique bridge was built in the early 19th century. One of its most distinguished features is that it spans the historic Moika River with the same width as neighboring St. Isaac's square and is almost three times as wide as it is long.
Blue Bridge was constructed in 1818 by architect V. Geste. Its construction was a part of architectural project of replacing the aging wooden bridges across the Moika River with single span iron arched bridges. Today's Blue Bridge was built following this design instead of earlier wooden bridge painted in blue color. In 1843, owning to the construction of the Mariinsky Palace and replanning of St. Isaac's Square under the project of engineer E. Adam, it was widened in the direction of Red Bridge and Antonenko Pereulok to its present day width.
The simplistically designed Blue Bridge is decorated with iron railings of the same design as the unique iron barriers that adorn the banks of the Moika River. Together with embankments and a square the bridge forms a harmonious and unique architectural ensemble.
The name of the bridge comes from the 19th century tradition of color-coding the bridges across the Moika River. It is one of four "colored" bridges, which have survived till today. Other remaining bridges are Red Bridge, Green Bridge and Orange Bridge.