I’ve been thinking a lot about refuge.

Across the British Isles, particularly on Scotland and Ireland’s rugged coastlines, stand the remains of ancient stone towers, some of them thousands of years old. They fascinate me. Most are on the wild and windswept coastlines; many are found on the remote smaller islands. People living in those exposed places built these fortresses of protection against sea-born raiders, slave traders, and invaders. Later came the famous round towers of Ireland that dot the countryside wherever a monastic village once flourished. In the Americas, there are the Anasazi cliff dwellings built halfway up enormous rock faces in such a manner that when the ladder was pulled up, there was no way to access the...