Here's some freqs licensed/used at Water Tower Place in the past:
WPOX914 (expired 2004) - 463/8.7375, 463/8.9875 mobiles, possible repeater pairs?
WPCI762 (expired 2003) - 464.425 repeater
WPXT750 (expired 2013) - 464.675 repeater (leaky coax / radiax?)
Please advise what (if anything) you find active there now.