The following fortifications served as the city's circular defense boundaries at some point in history: the Kremlin walls, Zemlyanoy Gorod (Earthwork Town), the Kamer-Kollezhsky Rampart, the Garden Ring, and the small railway ring. The Moscow Ring Road (MKAD) has been Moscow's boundary since 1960. Also in the form of a circle are the main Moscow subway line, the Ring Line, and the so-called Third Automobile Ring, which was completed in 2005. Hence, the characteristic radial-circle planning continues to define Moscow's further development. However, contemporary Moscow has also engulfed a number of territories outside the MKAD, such as Solntsevo, Butovo, and the town of Zelenograd. A part of Moscow Oblast's territory was merged into Moscow on July 1, 2012; as a result, Moscow is no longer fully surrounded by Moscow Oblast and now also has a border with Kaluga Oblast. In all, Moscow gained about  and 230,000 inhabitants. Moscow's Mayor Sergey Sobyanin lauded the expansion that will help Moscow and the neighboring region, a "mega-city" of twenty million people, to develop "harmonically."