Greyfriars Road was once the site of the old Greyfriars Priory. There are no remains of the friary today, although excavations in the 19th century did uncover a late 13th century church with 30 graves. The Greyfriars renounced worldly wealth and would beg for their daily bread. They followed St Francis and served the people working among the sick and the destitute.

You can see part of the Bute Docks feeder canal at Greyfriars. The banks of the canal here are mainly uncultivated bramble with a number of tree saplings between the ground cover of ivy, wild garlic, alum and cow parsley, which provide a great habitat for blackbirds, dunnock, wrens, wood pigeon, collared doves and squirrel. The nearby high rise office blocks act as an artificial cliff for roosting jackdaws and starlings.

As you cross underneath North Road to the castle, look out for hints of the old Glamorgan Canal. Set in the stone are the old workings for a lock that was situated here. The underpass is actually the old canal tunnel.

The route of the Glamorgan Canal ran across Queen Street, parallel to the Hayes and Woking Street - through what is now St David's Centre - behind Habitat, under Caroline St Bridge and down Mill Lane to the end of St Mary's Street. It then ran parallel to Bute Street in to Bute West Dock.

Cardiff Castle

The site of Cardiff Castle was first fortified by the Romans in about 75 AD. Later the Normans used the same site to build Cardiff Castle in the 12th century. The Castle was then rebuilt late in the 19th century by the Butes, who employed William Burges to restore the castle and to embellish it: adding detail, craftsmanship and colour to surprise visitors from many lands.

The old Roman walls are a Jurassic Blue Lias limestone from the Vale of Glamorgan, possibly from Aberthaw - this has been capped by a layer of coarse Radyr stone.

The reconstructed walls are limestone: east of the main gate a carboniferous limestone from Culverhouse Cross is used while those in the south east corner are a darker limestone from the Pentyrch-Creigiau area. Stone from the Roman walls was also subsequently used to build the Norman keep.

Look out for fossils in the castle wall - they're over 200 million years old!

Buzzards and kestrels are now breeding regularly in the inner city, look out for carrion crows and jays in and around the castle.

The corner of North Road and Castle Road is the area known as North Gate and is where the medieval town gate and wall would have been - the sloping floral display in the grounds of the castle here is actually supported by part of the old town wall. There are other places along the walk where you can see the old town boundary still marked, look out for Westgate Street later in the walk.