The Sweet 16 has traditionally been the most celebrated milestone on the road to the Final Four, and with good reason.
The 16 teams that remain have reached the tournament's second weekend by defeating two (or, if they competed in the tournament's opening round, three) high-quality opponents. They have survived intense, pressure-packed environments and battled through the fatigue of a long season. With the bright glare of the national spotlight upon them, they have stood tall and won.
The driving force behind the popularity of the NCAA Tournament is the unpredictability of it. To play Division I basketball, whether it be for a program as renowned as Duke or anonymous as Lehigh, requires special talent. You have to be really, really good to play for either school and, given that parity, upsets like the Mountain Hawks' amazing win over the Blue Devils can happen at any time.
The structure of the NCAA Tournament, with games being played on a neutral court and the limited amount of time to prepare for a specific opponent, creates an environment much more conducive to the upset victory, especially during the opening weekend.
The Sweet 16, however, is where the men are separated from the boys. It is very difficult for a team to sustain a hot streak over a four-day layover between games, especially considering all the travel involved and the element of surprise that comes with a lower seed advancing having worn off. That is why so many Cinderellas see the clock strike midnight in the Sweet 16.
That is not to say that the upset victory is no longer a factor in the drama surrounding these games. For one, higher seeds that would have been victims of an upset in the first weekend see the tables turned and find themselves trying to pull one off, as is the case when a No. 4 seed plays a No. 1 seed. Also, as recent history has shown in the cases of George Mason, Butler and VCU, college basketball's traditionally elite teams and conferences are no longer head-and-shoulders above the rest. David can truly slay Goliath.
With that in mind, here are the five most likely upsets of the Sweet 16.