I love stone walls , whether freestanding or as part a structure such as a castle. There are innumerable variations of texture , colour & style.
I am especially fond of drystone walls which do not require a concrete foundation. Friction between the stones gives them great strength if they are built properly.
Mortared walls tend to crack under climatic pressures especially freezing.

Most old castles and churches were built not of solid blocks but of local rubble which was later faced with veneers of stone. One of the main expenses associated with building was the cost of transport of stone. Sites strategically suited to castle building did not always have availability of local stone.

My uncle used to build & repair stone walls in England. Here , there are hundreds of miles of walls built largely in the 17th and 18th century as farms were developed from previously much larger holdings. The stones are generally of limestone and are smallish , flattish and ligthish. This is the opposite of dolerite. Dolerite walls are either bulky structures built from boulders (& somewhat unstable unless the base is very wide) , or of heavy awkward blocks which are hard to come by. Alternatively dolerite walls may be mortared togetehr to compensate for the lack of workability.

This year I built a low wall to replace an overgrown hedge. Several of the stones were very heavy , around 150-180kg. Here is a pic of the final effort. I ran out of this stone, but recently procured some more. It displays a nice yellowish hue from some oxide peculiar to this subtype of dolerite . I made sure to stack it nice & strong. Children tend to clamber on & over walls so wanted to avoid trouble.

2 miles up the road on a property where I gleaned my centrepiece Judgement Stone , are a collection of magnificent convict built dolerite walls. Age has given them a superb patina of lichen. Many of these quarried blocks are quite large and would have required 2-3 men to lift them into place. Labour was pretty cheap, providing you used convicts.