Line 1 is the first underground rapid transit line built in Milan, Italy. It is part of the Milan Metro and it is operated by ATM. Works on the line began in 1957, and the first part was opened on 1 November 1964, running from Sesto Marelli to Lotto station. The line is also called Red Line, as it is visually identified by red signs. Due to its premiership, the line gave its red color to the Milan Metro logo.