In the 19th century efforts to contain fire in New York City included the construction of an extensive reservoir system and the Croton Aqueduct, as well as the placement of round-the-clock watchmen at strategic vantage points. These men directed fire companies through an alarm code, corresponding to the severity of the fire and to numbered districts, transmitted by bells, flags and lanterns. City Hall, constructed in 1812 with a bell in its cupola, became the city’s first and main alarm. After a devastating fire in 1835 the Fire Department built dedicated towers across the city. The Mount Morris Fire Watchtower, also known as the Harlem Fire Watchtower, is the only surviving one of eleven cast-iron watchtowers placed throughout New York City starting in the 1850s. It was built by Julius H. Kroehl for $2,300 based on a design by James Bogardus. It is located at the top of a lookout plaza in Marcus Garvey Park in Harlem.