This year's NCAA men's basketball tournament has been notable for its upsets and its "Cinderella stories." Powerhouse Georgetown lost in the first round to 11th-seeded Virginia Commonwealth University—by nearly 20 points. Duke, last year's champion, fell in the Sweet Sixteen to fifth-seeded Arizona, by almost as wide a margin.

More remarkable than the giants who've fallen are the lesser-known teams that have advanced far into the tournament. After beating the Hoyas, VCU went all the way to the Final Four—making it one of the lowest-seeded teams in history to make it that far in the tournament. The team that beat VCU in the Final Four has had an even more impressive run: Butler University, an eighth seed, is about to make its second consecutive appearance in the championship game, this time against third-seeded University of Connecticut.

The success of both VCU and Butler this year, combined with Butler's strong performance last year, might leave tournament-watchers with the impression that "Cinderella stories"—low-seeded teams that advance further in the tournament than expected—are common. But despite these recent examples of low-seed advancement, stories like VCU's and Butler's are quite rare. Before this year, just two other eighth-seeded teams have made it to the championship game, and only two other 11th seeds had gotten as far as the Final Four.

Here, a look at the lowest seeds to reach each of the major rounds of the NCAA tournament: