Often overlooked by visitors heading for Snowdon, Llyn Pen-y-Gwryd is a small moorland lake just a few yards from the A4086 by the Pen-y-Gwryd Hotel. On most sides it's marshland and reeds, but the lake exists behind a stone dam and sluice - this being the best point of entry. For real swimming, it's proabably best to head for Llynau Mymbyr, a few miles further east, but if you're just wanting to cool off after trekking up Snowdon, then it's ideal. There's plenty of parking in lay-bys along the nearby A4086.