More than just another dam attraction, Grand Coulee Dam is the largest concrete structure in the United States. Built initially to irrigate land in the region -- and the dusty desert landscape around Grand Coulee suggests why this was so important when the project was conceived in 1917 -- it also provides power to a lot of the Northwest.

In damming the Columbia River, Franklin D. Roosevelt Lake was created, a 150-mile stretch of water garnished with campgrounds and boat launches. With this much lake-room in which to maneuver, houseboating is an understandably popular way to cruise; rent boats, both house-sized and in the row-boat category at one of the marinas at the lower end of Lake Roosevelt if you didn't think to bring your own; ski boats are also up for rent, but all boaters need to keep an eye out for swimmers practicing their stroke outside protected areas.

Next to boating, fishing is easily the lake's other lure - with the right license anglers can cast off right from the bank, though those equipped with a boat of some kind (and a guide) might prefer to seek out more solitary sweet spots offshore.

Nearby, big cities Coulee Dam and Grand Coulee boast populations of 900 a piece. From Grand Coulee, hiking trails lead up to the dam itself or around Coulee Dam. If you want a closer look at the big concrete slab blocking the river, take a tour through the dam for a briefing on its history and a look at the spillway, twice as high as Niagara Falls.

Grand Coulee Dam is 77 miles west of Spokane, and just over 140 miles east of Seattle.