Complex sentence: Rumbold in 1869 was to design the Missouri State Hospital (also called the St. Louis County Insane Asylum or City Sanitarium) which also features a dome and its location at 5400 Arsenal is the highest point in St. Louis.
Split into simpler sentences: Rumbold in 1869 was to design the Missouri State Hospital (also called the St. Louis County Insane Asylum or City Sanitarium) which also features a dome. Its location at 5400 Arsenal is the highest point in St. Louis.