 Tunnel and the Zakim Bunker Hill Bridge, which spans the Charles River.The underground construction of the tunnel system was completed as of October 2006; however, repairs continue to many parts of the tunnel due to water leakage because of improper construction of the slurry walls supporting the O'Neill tunnel.The former route of the above-ground Artery, so named "the other Green Monster" by Mayor Thomas Menino, was replaced mostly by open space known formally as the Rose Kennedy Greenway.