Its newest addition is the completion of the Bolshaya Koltsevaya line, a 70-kilometer loop that links 31 stations and which opened Wednesday.

The Bolshaya Koltsevaya line, known in English as the Big Circle Line (BCL), designated Line 11 and 11A is a rapid transit line of the Moscow Metro. It is the third circle line on the system, running outside of the existing circle Koltsevaya line and interlocking with Moscow Central Circle, with a temporary branch to Delovoy Tsentr station in Moscow International Business Center. It is the longest metro circle line in the world.

Costing an estimated $6.6 billion to build, the line is one of the largest infrastructure projects in Russia in recent decades. The BCL has 31 stations, with 24 of those providing 47 interchanges to existing and future stations of the capital’s metro.

The BCL will serve as an impetus to the capital’s development for decades to come, adding that it would help decrease the traffic flow on the city’s highways by up to 15 percent, and would decongest metro lines by up to 25 percent.

According to themoscowtimes