I am not talking about the MRT system. I see that everyday.
I am currently in Singapore and I swear I haven’t seen daylight in two days. My hotel is directly connected to this MRT and Mall. I am just underground and everything is so huge down here.
I wonder is this a city under the city?
maybe https://openlevelup.net/?l=0#11/1.3025/103.9049 to the extent that it is mapped in OSM?