3 ms·

To build (more of) a subway, you need density and wealth. So NYC or Shanghai or Moscow have extensive subway systems and keep extending them. OTOH Houston does

by nine_k 2y ago

To build (more of) a subway, you need density and wealth. So NYC or Shanghai or Moscow have extensive subway systems and keep extending them. OTOH Houston does not (lacks density), and Kinshasa does not (lacks wealth).