NCAA Tournament officially begins Tuesday and Wednesday with First Four action followed by first- and second-round games on Thursday and Friday as part of a rollercoaster opening week that will see the 68-team field quickly shrink to a Sweet 16 in the span of six days.

Auburn (South Region), Duke (East Region), Houston (Midwest Region) and Florida (West Region) are the four No. 1 seeds leading the 68-team field, while Texas, Xavier, San Diego State and UNC were the last four in. West Virginia, Ohio State, Indiana and Boise State were the first four out.