 Complete the following phrase:  In the early 1730s a section of the eastern river bank of the Ouse was improved, at the expense of the city, to create an area lined with trees along which the citizens could promenade. It proved so popular that within a few years this New Walk was extended further south past the junction with the Foss by way of a wooden drawbridge. This new bridge was painted blue and the colour and name have endured though the bridge itself has been replaced several times, the first of these being in 1768 when a single-arch stone bridge was constructed. In 1792 the Foss Navigation Company built a wooden swing-bridge to enable boats to access the Foss and this type of bridge was used again when the bridge was rebuilt in 1834. In 185758 an iron opening-bridge was built along with two stone plinths upon which stood two Russian cannons. These had been captured at the Battle of Sebastopol in 1855 and became the 