England’s Sweet Track and Post Track causeways rise from the Somerset wetlands
The Sweet Track, a mile-long wooden walkway across the marshes of what’s now Somerset, England, went up in roughly a single day around 3807 B.C.E. Neolithic farmers, working only with stone and flint, felled oak, ash, and lime with techniques matched to each tree. It’s among the earliest known examples of humans engineering a landscape to move through it.