Less than 7,000 miles of land lost in 70 million square miles of ocean, the remote Hawaiian chain of islands has always been a challenge for navigators. This episode highlights Kilauea Point Lighthouse, located on the Kilauea Point Wildlife Refuge on Kauai Island; Makapuu Point Lighthouse (above), the biggest and most powerful of the lighthouses in Hawaii, located on the eastern end of Oahu, Hawaii’s most populous island; and the Diamond Head Lighthouse, located near the foot of the extinct Diamond Head volcano. The beautiful and historic keeper's dwelling is now the official residence of the Coast Guard's 14th District Commander, Admiral Joseph McClelland.

Strewn with rocks (some still uncharted), mined with icebergs, often blanketed with fog and torn by ferocious storms, the seas around Alaska are some of the most treacherous on the planet. Yet, along Alaska’s 33,000 miles of coastline, only a handful of lighthouses were built to mark the way for ocean-going vessels, pleasure boaters and a fleet of commercial fishermen. Most lighthouses in Alaska were built at the turn of the last century, when gold was discovered, and none are accessible by road. All are reachable only by boat, plane or helicopter.

The Great Lakes, which have long served as an important liquid highway, are the busiest inland waterway on the planet. This program highlights the many lighthouses found along Lake Ontario, Lake Erie and Lake Huron.

The U.S. Gulf coast stretches for a thousand miles along five states — Florida, Alabama, Mississippi, Louisiana and Texas. This episode features the Biloxi Lighthouse — which now stands in the middle of four lanes of traffic in Biloxi, Mississippi — and the privately owned Aransas Pass Light Station in Texas. At one time, Texas had more than 50 lighthouses to mark its long and dangerous shoreline. Today, only a few remain in reasonably good shape and most are in private hands.