At St John's Church turn right in front of the church into Church St and then left into Trinity Street. Continue straight past the entrances of the market and Howells into The Hayes.

St Johns Church

St Johns Church is one of the oldest remaining medieval buildings in the city, dating from the 12th century. The original building is blue Lias, a local Jurassic stone full of fossilised shells, probably from Aberthaw. All that remains of the original building today is the west tower - dressings on the tower were originally Dundry Stone, an Oolitic freestone.

Extensions to the church in 1886-1897 used Carboniferous Limestone from Culverhouse Cross. The Churchyard wall is Lias with red sandstone copings of Devonian sandstones from the Forest of Dean.

The Hayes

Passing through The Hayes, notice the great old london planes, reputed to calm the nerves of stressed-out office workers. Did the town planners know this when they planted the area in the early 20th century?

Ginkgo biloba trees grow here, also known as the Maidenhair tree, which is native to China. It was introduced to Britain in 1761 - ginkgo fossils from the Jurassic Period are identical to the trees growing today - so in effect the plant is a living fossil that has not changed in 200 million years.

Take a quick look inside the St David's Centre. The pillars between the shops are brown and white Napoleon Tigre marble from northeast France - the cloudy patches within the stone made by shallow water algae are known as banding. Also look out for the line of the old town wall: originally this was marked with red-brown granite from South Dakota - this has now been replaced by a dark green-black Gabbro stone.