Visit the historic market that dates back to Roman times and see the modern-day architectural marvels constructed by the Victorians. Visit the historic Leadenhall Market and take a peek down Bull's Head Passage, where you might find the blue door that was used to film the outside of 'The Leaky Cauldron' pub in Harry Potter. Credit: PixabayYou might be surprised to know that the structurally spectacular Leadenhall Market, situated in the heart of London’s financial centre on Gracechurch Street, was once a bustling centre of commerce during Roman Britain. A rich historyThe market stood astride the gargantuan Roman basilica and forum (market), built and expanded upon between AD 70 and AD 120. Remains of the Roman basilica have been found near Leadenhall, including a large support foundation that would have held up an arch in the basilica’s arcades.