Complex sentence: In the 1950s Jackson Park's Wooded Island was almost leased to the Army to become the location of an anti-aircraft instillation, but was strongly protested against, as the Park District had given the Army other location options and Jackson Park's Wooded Island was spared.
Split into simpler sentences: In the 1950s Jackson Park's Wooded Island was almost leased to the Army to become the location of an anti-aircraft instillation. But was strongly protested against, as the Park District had given the Army other location options and Jackson Park's Wooded Island was spared.