From 1925 to 1956, a 147-square-mile territory on the Strait of Gibraltar was governed jointly by rival nations, with no income taxes, no banking laws, and courts that blended French and Spanish law. This episode explains how the Tangier International Zone grew out of a 1777 decision by the Moroccan sultan to confine European commerce to one port, the capitulation agreements that put foreigners under their own consuls, and the hygiene commission that slowly became a city council.

We walk through the 1906 Algeciras Conference, the 1923 Paris Convention, and the deliberately deadlocked institutions that left the city effectively ungoverned. That vacuum produced a banking boom from 15 banks in 1939 to 85 by 1950, a haven for smugglers and anonymous wealth, and a bohemian refuge for writers like William S. Burroughs and for gay men fleeing persecution. Then come Spain’s 1940 occupation, the postwar restoration, and Morocco’s 1956 reclamation.

• Why the chairmanship of the hygiene commission rotated every three months in alphabetical order
• Britain’s insistence on demilitarization to protect Gibraltar
• Why the United States and Italy initially refused to join the mixed courts
• How numbered accounts and absent oversight created a black box of untaxed money
• Ahmed Balafrej’s hard-line negotiation and the phase-out of the zone’s privileges by 1960