Russian reclusive maths genius Grigory Perelman did not appear in Paris on Tuesday 22nd June to collect his $1m prize for solving a problem that has puzzled scientists for more than a century.
Perelman, 43, was to be awarded the prize for proving the Poincaré conjecture, one of seven problems on the institute's Millennium Prize list.
Perelman, who lives in a small apartment in St Petersburg with his elderly mother, is unemployed and neighbours say he lives in poverty.
He has rejected job offers from several top US universities.