1) UNDERGROUND CITYThe Singapore government in trying to increase land in Singapore has built an underground city.
An underground city is defined as a network of tunnels built below the ground surface to connect buildings such as office blocks, shopping malls and train stations. Such a network of tunnels is usually built in the city centre. An example in Singapore is the underground city connecting the City Hall MRT station to various buildings in the nearby areas such as the Esplanade and some hotels in the Marina Bay area.