Support The Moscow Times!

In Photos: Moscow Metro Inaugurates 'World's Longest' Circle Line

First opened in 1935 with a single line and 13 stations, the Moscow metro has since expanded to encompass a sprawling underground network of over 250 stations.

Its newest addition is the completion of the Big Circle Line, a 70-kilometer loop that links 31 stations and which opened Wednesday.

Costing an estimated $6.6 billion to build, the line is one of the largest infrastructure projects in Russia in recent decades.

"The line has become the world's largest underground subway ring," President Vladimir Putin said via video link at the line's opening this week.

Here's a look at some of the 31 new stations on the Big Circle Line: