Grigory Perelman is a Russian mathematician known for his groundbreaking work in geometry and topology. He gained international fame for solving the Poincaré Conjecture, a famous problem in mathematics that had remained unsolved for over a century. His proof, published in 2003, was highly complex and required a deep understanding of various mathematical concepts. Despite his significant contributions, Perelman is known for his reclusive nature and refusal of prestigious awards, including the Fields Medal and a $1 million prize from the Clay Mathematics Institute. His decision to decline these honors has made him a unique figure in the mathematical community.