To reach Osea, situated in the Blackwater Estuary, you'll have to time the tides to drive over the tidal causeway. Osea's causeway is an extremely unique one, as it was built some 2,000 years ago ...

Osea Island, in the River Blackwater ... the cast and crew stayed on the island, accessible via a causeway from Maldon for a four-hour period every 12 hours. "What was so fantastic about this ...