Brunels Bridge was designed by Great Western’s engineer, Isambard Kingdom Brunel. It was built in 1838 but not brought into use until 1 July 1839. The two arches of the bridge are the widest and flattest in the world. Each span is 128 feet (about 39 metres), with a rise of only 24 feet (about 7 metres). It is testimony to the genius of Brunel that such a bridge with such flat arches was not only built but continues to carry the Great Western Railway main line from Paddington Station to this day.
The River Thames towpath passes under the right-hand arch which is also known as the Sounding Arch, because of its spectacular echo that can be heard.
Brunels Bridge and the Sounding Arch can be found a few minutes walk away from Maidenhead Bridge. Follow the tow path alongside the River Thames for around 500 metres and you will actually walk underneath the bridge where you can experience the amazing echo and see the bridge in all its glory. The plaque is to be found on the far side of the bridge.