121 Seaport, like 101 Seaport, is a new development, Class A office building. Unlike the 101, the oval-shaped tower sits above a rectilinear base containing a three-story lobby and two stories of retail amenities totaling 50,000 sq. ft. The project also includes rooftop terraces, a fitness center, below-grade parking and waterfront access. It utilizes twice as much vision glass as typical office buildings, with a composition that is structural steel, concrete core, and 80% glass. Energy efficiency measures include: use of a rain reclamation system, abundant natural daylight, chilled beam mechanical system, its streamlined shape reduces lateral loads and increases construction efficiency, and high plumbing fixtures throughout the building. 121 Seaport is part of the new 23-acre development happening in Boston’s Seaport Square.