Real Institute of Maths

Grigori Perelman: The mathematician who refused a million dollars:
Grigori Perelman is a Russian mathematician who solved the century-old Poincaré Conjecture but became a recluse by refusing both the prestigious Fields Medal and the $1 million Clay Millennium Prize. His story is one of a reclusive genius who values intellectual principle and truth above fame and fortune, choosing to withdraw from public life and the academic community he felt was corrupt.

Early life and career:
Born in Leningrad (now Saint Petersburg), Russia, in 1966, Perelman showed exceptional mathematical talent from a young age.
He won a gold medal at the International Mathematical Olympiad at age 16, which earned him admission to Leningrad State University.
He spent time in the United States in the 1990s on research fellowships at institutions like the Courant Institute and UC Berkeley, but declined lucrative job offers from top universities like Princeton and Stanford to return to Russia and live with his mother.

Solving the Poincaré Conjecture:
Perelman is most famous for proving the Poincaré Conjecture, one of the seven Millennium Prize Problems, a complex problem in topology that had stumped mathematicians for nearly 100 years.
He published his proof in three papers on the internet between 2002 and 2003, using a modified version of Richard S. Hamilton's Ricci flow.
His proof was independently verified by other mathematicians around 2005.

Rejection of honors and withdrawal from public life:
In 2006, he was awarded the Fields Medal but refused it, stating he was not interested in fame or money.
In 2010, the Clay Mathematics Institute offered him its $1 million prize for solving the Millennium Prize Problem, which he also refused.
Perelman explained that he disagreed with the decisions of the organized mathematical community and felt it was unjust.
He has since retired from mathematics altogether and lives in seclusion in St. Petersburg, Russia.
Source: Wikipedia