When did The Construction Of Aurora end?

In 1918 during the beginning of Aurora’s first building boom, Army General Hospital  (re-named Fitzsimons Army Hospital) was built east of town. Twenty years later, in 1938, Lowry Air Force Base was opened to the southwest of town. Rather than closing Fitzsimons, the U.S. government expanded and upgraded the hospital facilities in 1941 just in time to care for the wounded servicemen of World War II. Lowry expanded to a site 15 miles to the east in 1942 that eventually became Buckley Air National Guard Base and later Buckley Air Force Base.  

Explanation:

they would have to clean it very clean