Cawdor Castle in the Highlands, reached from the port of Invergordon — a 15th-century tower house still lived in, with its holly-tree legend and three walled gardens.

Aberdeen, Scotland’s silver Granite City, and nearby Crathes Castle — a 16th-century tower house with a rare Renaissance painted ceiling and eight walled gardens.

The marked circuit at Capelinhos on Faial is 3.8 km and about 90 minutes. What the ash field is like underfoot, the whaling harbour the eruption closed, and the lava pools at …