In the early hours of September 16, 1732, lightning struck the gunpowder magazine housed in the keep of Campo Maior Castle, in Alto Alentejo. The resulting explosion, followed by a fire, devastated much of the border town, killing hundreds and destroying its medieval core.
Estimates range from 200 to 256 deaths and over 2,000 injured, with 836 out of 1,076 recorded houses being destroyed or severely damaged. The castle and medieval walls suffered significant damage, shaping the urban layout visible today.
The tragedy prompted swift royal intervention, with King John V ordering reconstruction and granting ten years of tax relief to aid the town's economic and social recovery.
