or Evripos Strait
Narrow strait in the Aegean Sea.
Located between the Greek island of Euboea and the mainland of central Greece, it is 5 mi (8 km) long and varies from 130 ft (40 m) to 1 mi (1.6 km) in width. It has strong tidal currents that reverse directions seven or more times a day, a phenomenon still not fully understood. The main port on the strait is Chalkís , an important trading centre since the times of ancient Greece. A 130-ft (40-m) movable bridge spans the strait at Chalkís, replacing earlier structures that dated to 411 BC.