 The First Engineer Bridge is one of the most decorative of Saint Petersburg's more than 500 bridges.The original small wooden bridge, called the "Summer Bridge" and rumored to have been designed by the architect Bartolomeo Rastrelli, was built in the 1760s.This bridge was replaced with the current cast-iron bridge, in 1824-1825, and renamed the First Engineer Bridge, in 1829, after the nearby Engineers' Castle (originally called "St Michael's" or "Mikhailovsky Castle").