This Road Vanishes Underwater Every Day, Beauvoir-sur-Mer

Twice a day, a road in western France disappears into the sea. The Passage du Gois is a paved causeway about 4.1 kilometers (2.6 miles) long, linking the mainland at Beauvoir-sur-Mer to the island of Noirmoutier. It isn't a bridge or a raised embankment. It's a road laid across a natural sandbank in the Bay of Bourgneuf, and when the tide comes in, the Atlantic covers it. Noirmoutier was once reachable only by boat. Over centuries, the bay silted up, forming a sandbank that people and animals could wade across at low tide. The name is often traced to an old local word, goiser, meaning to walk with your feet in the water. The crossing appears on a map by 1701, and a regular route was established around 1840. The road was later paved and widened into the one drivers use today. The rules are simple and absolute. The road can be crossed for about an hour and a half before low tide and an hour and a half after. For the rest of the time it sits under the sea, as much as about four meters (13 feet) deep at high tide. Signs at both ends post the day's safe window. Parking on the causeway is forbidden. The water comes back fast, and every year some visitors misjudge it. For them, the road has refuge beacons, tall poles with platforms spaced along the causeway, where anyone caught by the rising tide can climb up and wait for rescue or for the water to go out again. Today nine of them line the route. At low tide, the causeway fills with people. Cars park on the sand, and families walk out onto the mudflats with buckets and rakes to dig for clams, cockles and oysters. The Gois has had its moments on a larger stage. In 1999, the Tour de France sent riders across it during the race's second stage. The wet, slippery surface caused a crash that split the peloton by six minutes and cost several favorites the race. The Tour came back in 2011 and used the causeway as the start of the first stage. Every year, runners in the Foulées du Gois race against the incoming tide. Since 1971, a bridge has connected Noirmoutier to the mainland farther south, at Fromentine. The old road across the sand is still used, twice a day, whenever the sea allows it.