Build It Bigger
Bigger is better as this series about mammoth-scale engineering projects returns. The season premiere takes architect/host Danny Foster to the site of the new Dallas Cowboys stadium—a $1 billion–plus, 3-million-square-foot undertaking that will include 80,000 seats, two 180-foot-long high-def video screens, and the largest retractable roof ever constructed. Monday, April 20, at 10 p.m., Science Channel

Frontline: Poisoned Waters
The continued pollution of such iconic waterways as Chesapeake Bay and Puget Sound is “a ticking time bomb,” journalist Hedrick Smith warns in this unsettling report, timed to coincide with Earth Day. Chemicals from consumer products, Frontline suggests, have caused such phenomena as oxygen-deprived dead zones. Meanwhile, “endocrine disrupters” are mutating fish in the Potomac River—and could harm human health. Tuesday, April 21, at 9 p.m., PBS; check local listings

Eco-Trip: The Real Cost of Living
David de Rothschild hosts this eight-part series assessing the environmental impact of everyday products. Episode 1 shows the damaging effects of conventional chocolate production and examines the organic alternative. Carbon Cops, a series in which families undergo energy audits, follows at 9:30 p.m. Tuesday, April 21, at 9 p.m., Sundance Channel

Garbage Moguls
Zealous young “eco-capitalists” devise and market products made from garbage in this engaging and frequently funny look at New Jersey–based company TerraCycle Inc. The film chronicles two offbeat inventions. The company hopes to sell a messenger bag—made from old billboard materials and seat belts—to OfficeMax. WalMart, meanwhile, may be interested in a kite created from cookie wrappers—if it ever gets off the ground. Wednesday, April 22, at 9 p.m., National Geographic Channel

Waking the Baby Mammoth
In May 2007, a reindeer herder made an extraordinary find in a remote corner of northwestern Siberia: the remains of a 1-month-old woolly mammoth, preserved in remarkable condition for 40,000 years. National Geographic travels from Russia to Japan to follow the forensic examination of “Lyuba” as scientists seek clues to the millenniums-old secret of what wiped out her species. Sunday, April 26, at 9 p.m., National Geographic Channel

Other highlights

Jean-Michel Cousteau:
Ocean Adventures—Call of the Killer Whale

The explorer and his team travel from Atlantic to Pacific in search of orcas, the dominant predators of the ocean. Wednesday, April 22, at 9 p.m., PBS; check local listings

Return to Tarawa
Cameras follow an 89-year-old veteran’s emotional effort to clean up the site of one of World War II’s bloodiest battles. Friday, April 24, at 10 p.m., Military Channel