Maintaining over 700 military bases across the world, endless war (handouts to Military-Industrial-Congressional Complex companies), corporate welfare, foreign aid, public art, Africa, etc...
FYI the last three items amount to about 2% or less of Federal spending. All discretionary spending was 16% in 2016:
https://upload.wikimedia.org/wikipedia/commons/thumb/c/ca/U....
Excluding entitlements (Social Security, Medicare, debt service) it's still minuscule:
http://memepoliceman.com/wp-content/uploads/2015/09/viper-re...