A causeway is a raised road or path built across water or wet ground. Think of it like a bridge, but instead of arching high above the water, a causeway sits low and flat, just above the surface.

The ancient Romans built causeways across marshes and flooded areas so their armies could march straight through instead of getting stuck in mud or having to go miles out of their way. Today, you might drive across a causeway to reach an island: the road stretches across the bay or lake, with water on both sides of your car.

Causeways differ from regular bridges because they typically rest on material piled up from the bottom, creating a solid path, rather than spanning the gap with arches or cables. Some causeways are ancient. The Sweet Track in England, built over 6,000 years ago from wooden planks, let people cross a swampy area without sinking into the bog.

When you hear about a causeway, picture a straight road boldly cutting across water, connecting two pieces of land that would otherwise be separated.