Leó Szilárd
On 12 September 1933, the Hungarian physicist Leó Szilárd, an exile from Nazi Germany, was crossing Southampton Row at the junction with Russell Square when he had an insight that changed the course of history. He realised that splitting an atom with a neutron could produce further neutrons which themselves could also split atoms, leading to a chain reaction and a massive release of energy. This led directly to the development of the atomic bomb and nuclear energy.