Last week's answer

Question: In 1942, the U.S. Army Corps of Engineers undertook the massive task of carving the 1,700-mile Alaska Highway through the uncharted wilderness of Canada and Alaska. The biggest engineering nightmare the crews faced wasn't mountains or cold weather—it was muskeg, a subterranean bog made of decaying vegetation and water that would instantly swallow heavy bulldozers. How did engineers successfully stabilize the roadbed across miles of this bottomless mud?

Answer: They laid down millions of logs side-by-side to create a continuous wooden "corduroy road," distributing the weight of the highway and fill material over the swamp.

Surveyors initially tried to work around the muskeg, but elected to corduroy the road after that was deemed impossible. The process included chopping trees down by hand, layering logs across the muskeg along the planned roadway and pouring fill over the logs. Though time consuming, it was the only way forward.

Sources: PBS