Tower Bridge bridge's upper walkways. The pedestrian walkways are above the river at high tide. The main bridge deck carries two lanes of road traffic between two low-level pedestrian walkways across both suspension spans and the opening bascule section of the bridge, with the walkways separated from the roadway by fences. The roadway passes through each of the two towers, whereas the low-level walkways pass around the outside of the towers. One of the chimneys on the bridge, which are often mistaken for lamp posts, connects up to an old fireplace in a guardroom of the Tower of London. It is long-disused.
Tower Bridge was suspended from the middle of each walkway (or a red light at night) this indicated that the bridge could not be opened. These signals were repeated about downstream, at Cherry Garden Pier, where boats needing to pass through the bridge had to hoist their signals/lights and sound their horn, as appropriate, to alert the Bridge Master. Some of the control mechanism for the signalling equipment has been preserved and may be seen working in the bridge's museum. Tower Bridge is still a busy crossing of the Thames: it is crossed by over 40,000 people (motorists, cyclists and pedestrians) every