Today, 19 August, marks 55 years since Strelka and Belka boarded the Soviet spacecraft known as Korable-Sputnik 2. They were the first dogs to survive a trip to space.
Strelka and Belka were joined by 42 mice, two rats, a grey rabbit, some flies and several species of plants and fungi on their space mission. Together, they orbited the Earth 18 times.
Their pioneering trip is widely regarded as leading the way for Soviet cosmonaut Yuri Gagarin to make his momentous voyage to space, becoming the first man to do so.
In honour of Strelka and Belka, the Science Museum in London will soon launch a new exhibition that commemorates their space mission, entitled Cosmonauts: Birth of the Space Age.
The exhibition at the Science Museum will open on 18 September and will run until 13 March.