What's the maximum number of houses you can build on one Monopoly property before upgrading to a hotel?

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Which Old Testament woman helped Deborah and Barak defeat Sisera? Which woman prophetess briefly ruled Israel during the Judge era? What colorful farming game published in 2009 by Zynga gained popularity on Facebook? Who was the first African American U.S. Senator? What medical device is used to hear heartbeats?