Neither longtime Turkish leader Recep Tayyip Erdogan nor his main challenger Kemal Kilicdaroglu were able to win more than 50% of the vote. That means Turkey is heading for a runoff on May 28.

A struggling economy and slow earthquake response add up to a tough election for President Recep Tayyip Erdogan, who has dominated Turkish politics for the past 20 years.

Here is a look at the man expected to be the top challenger to President Recep Tayyip Erdogan's 20-year rule in the May 14 Turkish election, and what sets him apart.