Mont-Saint-Michel

Before returning to Washington on Wednesday, Biden will tour a historic venue in France, Mont-Saint-Michel, a 1,000-year-old Benedictine abbey that was listed as a World Heritage site in 1979.

"In order to transmit, one must preserve, but for decades Mont-Saint-Michel threatened to silt up completely, which would have realised the old dream of English generals, to take the mount as if it was a hilltop amid fields," Macron said during a visit to celebrate the monument's 1,000th anniversary.

An old dam across the Couesnon River in front of the mount protected agriculture and nearby town Pontorson from floods, but had also stopped the river's vigorous outflow during low tide that had flushed sediment out into the bay and for centuries helped Mont-Saint-Michel remain an island during high tide.

Discover the D-Day landing beaches in Normandy, along with Mont-Saint-Michel, the UNESCO-listed island monastery.

Health authorities have banned the fishing and selling of oysters in the bay around Mont-Saint-Michel and other shellfish farming areas on France’s north-western coast until further notice.