Jonathan's journey celebrating Britain's architecture takes him to St Paul's Cathedral in London. If one structure captures the spirit of London, this is it. Beautifully crafted and designed by the great Sir Christopher Wren, it is simply stunning in its stature, with its iconic dome that has dominated London's skyline for over 300 years. With unprecedented access to secret parts of St Paul's, Jonathan, aided by champion climber Lucy Creamer, climbs over 300 feet to investigate the innovations and tricks of the trade that architectural illusionist Christopher Wren employed to create this magnificent cathedral. He tests the limits of his courage to abseil over 220 feet straight down the centre of the dome from the cupola to get a completely unique view of St Paul's. He reveals how not everything at St Paul's is at it seems, as he uncovers the magic behind the greatest of Wren's architectural tricks.