Largest pedestrian subway network

The largest pedestrian subway network is the RÉSO (better known as "La ville souterraine" or the "Underground City") in Montreal, Canada. This network of shopping areas is linked by more than 32 km (19.8 mi) of tunnels and has a total floor area of around 3.6 km2 (1.38 sq mi), as of November 2023.

RÉSO's most recent round of expansions took place in 2003, when work in the Quartier International de Montréal joined up to some previously unconnected sections of the system. After the completion of this work, it became possible to cover a straight-line distance of more than 1.7 km (1.1 mi) through the city centre without once coming up to the surface – a much-appreciated feature in Montreal where winter temperatures routinely drop below -20 C (-4 F).

In recent years, many Chinese cities have been investing heavily in what is known as Urban Underground Space, but these projects are typically tied to specific commercial developments and not linked up into a city-wide system.