Volunteers at Mazzetti started rebuilding healthcare facilities in Haiti nearly four years ago, and a cholera treatment center is underway. "We don't want to just fly in with our cape and say we will build you a facility then fly out," says Mazzetti's Arash Guity. Arash just got back from Liberia, where he's helping compile a national set of health infrastructure standards. Mazzetti's first project in Africa, a pediatric hospital, is about to start construction. It's working on five new facilities across Sub-Saharan Africa.

Arash, Mazzetti's chief sustainability engineer, says water and energy account for just 5% of a US facility's operating budget; in Africa, they can be 70%. That means being more efficient with resources in Africa is "a necessity," not a luxury. Here, construction workers make building blocks from scratch onsite with a mixture of cement, sand, and water (no fancy equipment needed). Arash thinks that US projects can benefit from such simple design principles and reverse innovation. He'll head to Malawi in mid-December to mentor Engineers Without Borders' Cal Poly chapter. (That means Christmas in Africa and New Year's in an airport.)