Fermat's last theorem
It is impossible to find whole numbers for a, b, c such that
aⁿ + bⁿ = cⁿ
where n is a whole number greater than 2.

Fermat's last theorem had not been proven for 358 years since a French mathematician Pierre de Fermat hypothesize in 1637. Andrew Wiles, who spent most of his research time on this famous problem, finally proved it in 1995. His achievement is the most highly-publicized mathematical event of the 20th century.

After solving the problem Andrew Wiles expressed his emotion in the video: