The city of Kronstadt, located on Kotlin Island, is the first to greet guests of St. Petersburg arriving by water from the Gulf of Finland. For a long time, it was an impregnable fortress with a convenient harbor for ships, serving as a serious obstacle for the enemy fleet.

To this day, some fortifications have been preserved, such as the Northern Rampart, barracks, gates, and the Kronverk Canal. Now, this once-defensive waterway consists of six autonomous bodies of water located along the fortress wall in the area of Citadel Highway and Vostaniya Street.

The canal is recognized as a monument of hydraulic engineering from the 18th century, although its creation faced many obstacles, including catastrophic floods, wars, and budget shortages. Despite this, the canal remains an interesting attraction on Kotlin Island, although its significance has diminished due to the growth of urban infrastructure.

The history of the Kronstadt fortress began in 1703 when Swedish ships controlled the Gulf of Finland and threatened St. Petersburg. To protect it, Peter I laid the foundation for a fort on Kotlin Island, which was built in just one winter. Seventeen forts were constructed at the entrance to the Neva Bay, ensuring complete control of the water area.

The central structure on Kotlin Island was positioned so advantageously that no enemy ship passed by it throughout the city's history. This was confirmed by the summer campaigns of the Swedes in 1704-1705 when they unsuccessfully attempted to attack Kronstadt. Even during the Great Patriotic War, Kronstadt did not surrender its positions despite bombings and the blockade of Leningrad.

At its consecration, the fort was named Kronshlot, which translates from Dutch as "crown castle." The architect was the Italian Domenico Trezzini, who introduced Western European traditions into Russian construction.

According to Peter I's plan, the structure was surrounded by water. The Kronverk Canal was designed as a diagonal moat along the northern wall of the fort, separating it from the rest of the island. The width of the channel varied from 26 to 32 meters.

The creation of the canal took 12 years, but in September 1732, a devastating flood swept away the Kronstadt dam and buildings. The project was halted and abandoned as more important state matters were required, including the construction of stone fortifications.

In 1785, Catherine II signed a decree to move the Admiralty to Kronstadt, which defined the city's appearance. Alexei Samuilovich Greig deepened the harbor, opening up space for ship maneuvers. The builders were convicts.

In 1824, a new flood claimed the lives of hundreds of people and destroyed buildings. Kotlin Island was completely submerged. The city's restoration was carried out around the clock under the guidance of Count Pavel Petrovich Sukhtelen and Lieutenant Colonel Mikhail Lavrentevich Lvov. The aftermath of the flood was eliminated in two years, and a new city plan was approved, including the revival of the Kronverk Canal.

Its restoration continued from 1826 to 1848. In 1891, the length of the canal was reduced with the emergence of the Cabotage Harbor and Citadel Road. Gradually, the canal lost its defensive significance, with the last battle occurring in 1944. In 1996, entry to Kronstadt became free. Today, locals refer to the canal as the "Amazon."

Currently, the chain of water bodies remaining from the canal spans 1800 meters. Despite its status as a monument, they are polluted with lake, sea, and technogenic deposits. In some places, the layer of silt and debris reaches 80 centimeters.

In St. Petersburg, "Kronverk Canal" refers to three water bodies: the channel along the Peter and Paul Fortress and the Kronverk surrounding it, as well as the Kronverk Strait from the Neva River. Since 2017, authorities have been conducting work to clean and restore the canal, strengthening the banks and deepening the water bodies to ensure water circulation.