Remote, atmospheric, and astoundingly little known, Tre'r Ceiri is one of the most impressive ancient monuments in Wales. Today parts of the 4th-century fort's outer walls are still intact (rising more than 18 feet in places), and within are the ruins of 150 stone huts. They were inhabited by a Celtic tribe known as the Ordovices, and may have survived as a settlement for up to 700 years. From Porthmadog, take the A497 west, then turn left onto the A499 just before Pwllheli.
At the village of Llanaelhaearn, turn left onto the B4417. Less than a mile down this road is an unmarked footpath on the right leading straight up a hill to Tre'r Ceiri.
B4417, Llanaelhaearn, Wales