Walking Newcastle's streets, you'd never know this extraordinary tunnel runs for 2.5 miles beneath your feet. Built between 1839 and 1842 as a coal-wagon thoroughfare, it was used as an air-raid shelter during WWII. Volunteer-led, two-hour tours take you through an atmospheric 700m-long level section of the tunnel. Book ahead as numbers are limited, and wear good shoes and a washable jacket for the limewashed walls; it's not suitable for kids under seven. Tours finish back at the Victoria Visitor Centre.

　　Special one-hour family tours (including for under sevens) operate during school holidays.