In 1984 I was sent to live in Amsterdam with anarchist squatters. Like some half-remembered dream, on my final night in the city we were walked down dark back streets through an abandoned neighbourhood before arriving at a tall building with a heavy front door. The man leading our party banged forcefully and a shutter opened. Dutch pleasantries were exchanged, and we were allowed to enter. Down a dimly lit corridor we passed and along the wall, in a neatly arranged display was a long line of baseball bats, each with its own gas mask.