McTavish reservoir, Underground water reservoir and park near McGill University campus, Montreal, Canada.

McTavish Reservoir is an underground water storage facility built into natural rock walls that holds millions of gallons to supply the city. The grounds above feature pump houses in Châteauesque style and a sports field that shape the appearance of the site.

A major fire in mid-19th century Montreal revealed critical gaps in the city's water supply, prompting authorities to build this facility. Construction between 1852 and 1856 established a reliable water system to prevent future disasters.

The grounds serve as a meeting place where McGill University students and local residents gather for recreation and community activities. People from the neighborhood use this space regularly, making it part of daily life in the area.

The reservoir sits on Mount Royal's southern slope beside McGill's campus, with Rutherford Park on top reached from McTavish Street. The city tried to close the park in 2009 citing terrorist threats, but it stayed open to the public as of March 2021. The cliff formed during construction is used for ice climbing in winter.

The cliff left by the reservoir's construction is used for ice climbing in winter, in the middle of downtown Montreal. The same rock was blasted in 1852, sending boulders through the roof of the McGill College Building, now the Arts Building.