Complex sentence: It was built in the 1930's, was only intended originally to house a few thousand inmates.Follwing the Rwandan genocide, the numbers increased to above 50,000 as a large proportion of the inmates were genocidaires.
Split into simpler sentences: It was built in the 1930's, was only intended originally to house a few thousand inmates. Following the Rwandan genocide, the numbers increased to above 50,000 as a large proportion of the inmates were genocidaires.