Tankies like to note the nationalists at the protests, but ignore everyone else present. The protests began after the Ukrainian president reneged on an EU integration deal and then truly took on massive scale when Yanukovych's police violently cracked down on the protesters- many who were college students and young adults. Dozens would be killed by the police.
Polling suggests potentially upwards of a fifth of the country participated in some form in the Maidan Revolution with ~5% participating directly in Kyiv.
President Yanukovych would eventually flee to Russia with the Ukrainian Rada replacing him with an acting government till new elections were held that following spring.