The Indian Institute of Geomagnetism's Colaba Observatory sits on the edge of town and has been recording geomagnetic and seismological data for over a century. The grounds are not formally open to the public, but the historic buildings can be seen from outside and the institute occasionally hosts open days.
Of more interest to most visitors than the science is the leafy compound and the early colonial bungalows — a small slice of pre-independence Bombay province preserved here in plain sight.