Tickets are on sale now for a rare chance to go behind the scenes at Tower Bridge.
The bridge may be closing to traffic for three months but that's not stopping the popular Engineering Tours, which always sell out.
See the inner workings of the famous bridge, including a visit to the bascule chambers and the bridge control room.
The first part of the tour, led by one of the bridge's guides, includes a visit to the Tower Bridge Exhibition which explains the history of the bridge and its construction. Visitors can walk across the walkways above the Thames and visit the bridge’s engine rooms, which house the restored steam pumping engines, accumulators and boilers that powered the bridge lifts until 1976.
An added bonus of this year's tours is looking through bridge's glass floor will give visitors on the tour a unique view on the conservation works taking place.
The bridge’s senior technical officers lead the second part of the tour, visiting areas normally out of bounds to the public, including the bridge control room and the bascule chambers below the river. You'll also see the hydraulics that power the lifting of the bridge, and can ask questions about how the bridge works.
Tower Bridge Engineering Tours take place Saturdays and Sundays 5 November-31 December. Tickets (including a souvenir guide book) are £50 and must be booked in advance.