Tucked away amid deep forests and surrounded by rolling hills, this evocative, misty glen is a truly magical place. First established by a monk known as St. Kevin in the 6th century, Glendalough was originally devoted to Christian worship and scholarly learning. Sacked first by the Vikings and later by the English, it was eventually abandoned by the monks who sought refuge here. Those beautiful round towers were actually hideouts with retractable ladders that the monks would pull up after them when the raiders arrived. Most of the buildings were destroyed in repeated attacks, but enough survives to ensure the ruins are a striking and atmospheric spectacle. The site sprawls, so stop by the visitor center at the entrance to pick up a map. Each of the many walking trails traversing the area takes in different hidden ruins among the lakes and hills. Highlights include the oldest ruins, the Teampall na Skellig, across the lake at the foot of towering cliffs (unfortunately there’s no boat service and they cannot be visited), and the cave known as Kevin’s Bed, believed to be where St. Kevin lived when he first arrived at Glendalough. Follow the path from the upper lake to the lower lake to walk through the remains of the monastery complex. There’s a nearly perfect round tower, 31m (102 ft.) high and 16m (52 ft.) around the base, as well as hundreds of timeworn Celtic crosses and several chapels. One of these is St. Kevin's Chapel, often called St. Kevin's Kitchen, a fine specimen of an early Irish barrel-vaulted oratory with a miniature round belfry rising from a stone roof. Climb the hills to take in the beauty of this extraordinary site from above.