Since time immemorial, people have felt a need to surround themselves with safe, sturdy enclosures to keep out those who would cause them grief. In the medieval age, rival families and differing claimants to the throne often did bloody combat, which made the need for strong enclosures a matter of live or death. Consequently, hundreds of castles sprang up, some were made of primitive earthy materials while others were made of stone and brick.

A visitor to Celtic Britain - Wales, Ireland and Scotland - will notice many of these picturesque, historical gems in their travels. If fascinating history is on your agenda, the suggestions below are some of the best destinations from which to choose.

The Castles of Wales

Wales is a country of mystery, a mixture of vast ancient pastures and dreary mountain terrain. It was not with an easy transaction that the Norman French warriors, the conquerors of England, acquired this land. It took centuries of combat to fully integrate British influence, and the first castle of interest is a reminder of Norman presence in this fierce Celtic land.

Pembroke Castle lies in Pembrokeshire in Southwest Wales. This medieval edifice is one of Wales' biggest fortresses, owned by a lord of the realm. Sandwiched in the middle of two inlets, the castle saw much renovation throughout the centuries and different periods of construction are visible in its aged walls. Roger, the Earl of Montgomery, was responsible for the conception of the original Pembroke, and it withstood enemy fire even in that weak state. Over time, the fortress came into the possession of that quintessential knight, Sir William Marshall, who modified the structure, rebuilding in stone.

Pembroke is rich with enticing places to explore, such as ancient towers and parapets, and a massive twisting staircase. If you journey down the spiral stairs, you are greeted with a natural cavern hollowed out by years of water erosion, not an ordinary sight in a medieval castle. If you are an aspiring climber, the views of Pembrokeshire after reaching the top are well worth the exertion. The darkest feature of Pembroke, and possibly the most alluring to thrill seekers, is the single small hole into which unfortunate criminals were dropped. There they were never again to see daylight, and the place of the dungeon was named "Oubliette," French for "forgotten."