Toms had been a trade-union organizer in Luton when the war broke out, and he chartered the first ship to Spain he could find once news reached him: a tramp steamer from Southampton to Bilbao. On arrival, he found that the advancing Nationalists had cut Bilbao and the Basque Country off from the rest of the Spanish Republic. Denied the ability to join up with the International Brigades, Toms fought and organized as best he could.

As a trained surveyor and architect, Toms was given a position building the Iron Ring–fortifications intended to protect Bilbao from Nationalist assault until Republican troops could break through and link up with the isolated Basque Country. He did this with gusto, developing the laborers under his leadership into an effective and politically active unit known as “los topos de Tomás”–Toms’ Moles.

The local Republican commanders eventually became unsure of Iron Ring architect Alejandro Goicoechea’s loyalty. They therefore contacted Toms and had his men construct a bunker separate from the rest of the fortifications, into which the precious metal holdings of the local Bank of Spain and other valuables were placed to protect them from bombardment.

When, as feared, Goicoechea defected to the Nationalists with the complete blueprints of the fortifications, Toms and his men sealed their vault with explosives. None of them survived the retreat from Bilbao or disastrous Battle of Santander.

The bunker? It remains sealed until today, its exact location a mystery taken to Toms’ grave.

Or is it?