The striking thing about St. Petersburg's amazing subway system (like Moscow's) is that it is extremely deep. It was dug by nearly free peasant labor in the 1930s and—after a break for World War II—finished in the 1950s. While London's impressive system feels rickety, St. Petersburg's feels industrial-strength and bomb-hardened. Getting around by metro is second nature for locals. Today millions of citizens who use the system spend a good part of their lives—about an hour a week—riding escalators like this. Subscribe at http://goo.gl/8iBEnS for regular blog updates from Europe.