https://www.youtube.com/watch?v=dkULs_7vgDA
https://www.wmata.com/content/dam/wmata-com/maps/system-map-rail.pdf
https://en.wikipedia.org/wiki/Washington_Metro Daily ridership of 545,900 (weekdays, Q1 2026)
https://en.wikipedia.org/wiki/Washington_Metro#Busiest_days
https://en.wikipedia.org/wiki/Washington_Metro#System
https://en.wikipedia.org/wiki/Washington_Metro#Architecture
https://en.wikipedia.org/wiki/Washington_Metro#Planned_or_proposed_projects