Mont Saint-Michel, France

Postcard US-3133043 from Texas was a French postcard the sender collected during a trip to
Mont Saint-Michel in Normandy, France. Located 1 kilometer  or 0.6 miles off shore at the mouth of the Couesnon River, the tidal island is 100 hectares or 247 acres in size with only 44 official residents in 2009. However, as part of the UNESCO World Heritage Site, it has more than 3 million visitors each year.

Ten thousand visitors to the island got to see a supertide this Saturday on March 21, 2015, caused by the so-called supermoon effect coinciding with Friday’s total solar eclipse on March 20, 2015. Said to rise at the pace of a horse’s gallop, the unusual high tide turned the Mont briefly into an island fully surrounded by the English Channel Saturday. Normally, at a low tide visitors could walk on the vast flat seabed, while at high tide visitors could still travel to/from the mainland by a narrow causeway. The rare phenomenon supertide occurs every 18 years.

In Mount's Bay, Cornwall, United Kingdom, St Michael's Mount was a Cornish counterpart of Mont Saint-Michel in France, with the same tidal island characteristics and a similar conical shape,

St Michael's Mount

Postcard GB-537114 from UK shows St Michael's Mount, a tidal island off the Mount's Bay coast of Cornwall, England, United Kingdom. The island's history can be traced back thousands of years ago as a busy trading port in Europe. According to Wikepedia, St Michael's Mount was a Cornish counterpart of Mont Saint-Michel in Normandy, France, given to the Benedictines, religious order of Mont Saint-Michel by Edward the Confessor in the 11th century. It became a major destination for pilgrims. In 1659, St Michael’s Mount was purchased by Colonel John St Aubyn, the last military governor of the island’s garrison. It became his private home and his descendants are still live there today. The Mount was gifted to the National Trust in 1954.

366 meters or 1200 feet across the town of Marazion, St Michael's Mount is one of the 43 unbridged tidal islands that can be walked to and from mainland Britain, by a man-made causeway.