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One of my best friends ran more than 10 marathons, and he smokes up to the night before! Don't know how he manages...
But he has also run two "Marathon du Médoc" which is in the Médoc wine region. And that's a special one because you run the full distance (but slower than usual) and every few km you stop at a castle, taste some wine, eat oysters and other things, dance for a bit to various bands or orchestras, and then you continue to the next stop. The contestants wear costumes too. It's a riot, and if ever I run one, it will be that one.
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100 is a respectable age! my grandma just turned 96, and she is still a fun and happy lady, although she must take things pretty slow physically.