
Four biggest metro areas in the Americas and their metro systems on Apple Maps
(Source: reddit.com)

The Maltese Underground Proposal
A proposal for a three-line underground metro system with 25 stations around Malta was unveiled by the government on Saturday.
The network would cost around €6.2 billion and take 15 to 20 years to build, according to studies by London-based consultants Arup Group. A proposed first phase would cost €3.9 billion and could be operational in five to eight years.
(Source: timesofmalta.com)

The five deepest metro stations in the world are located in North Korea, Ukraine, Russia, US, and UK respectively. Portland, OR holds the deepest in the western hemisphere.
(Source: twitter.com)

Proposed underground metro “tube” system for Birmingham (UK) and the West Midlands
(Source: reddit.com)