Mexico City's Metro Line 4 is the shortest and least-used line in the system. As such, it's a boon for international visitors.
It's light ridership can be mostly explained by the fact that it's never been completed. Numerous proposals to extend the service, northward and southward, have fallen by the way side.
Even still, as it's mostly an elevated line, it offers some tremendous views. Metro Line 4 crosses much of the densely populated and little-known east side of Mexico City.
For those struck by the idea that Mexico City is in fact a great storehouse of little-known facts, historical curiosities, and secrets, it's a terrific day of exploring. Just arriving to the Jamaica Market or Santa Anita in the south, or Martín Carrera in the other direction will