Former Bank of Japan Hiroshima Branch: Vaults
The underground bank vaults, now open to visitors, are one of the building's most impressive features, having survived the atomic bombing almost entirely intact. Located behind the main hall, the vaults sit beneath the courtyard area and were lit by a central skylight. The building's numerous windows—an uncommon feature at the time—were partly meant to filter as much light as possible into the underground vaults.
The bank’s two vaults were also the state of the art for the time. The 90-centimeter-thick steel doors and the similarly well protected ventilation shaft beside them appear both imposing and impregnable. However, the security does not stop at the vaults’ doors. Surrounding the vaults are four wide corridors, which provided protection from flooding and also ensured no one could simply tunnel straight into the vaults from outside. The carefully placed mirrors where the corridors meet allowed patrolling guards to see around corners without having to move.
Perhaps unsurprisingly, the thick steel vaults survived the bombing, but the blast and resulting fires created intense heat around them. The paper money inside the vaults, which would otherwise have burst into flames, was spared because the vaults also contained large pots of water for putting out fires. The water evaporated, cooling the vaults and keeping the money intact. Today, the vaults are used for rotating exhibitions of photographs and artifacts related to the atomic bombing.