Horses' hooves thundered over the cool grass of Chesterfield's Smith McGehee Polo Field this chilly September afternoon as spectators cheered and sipped wine on the sidelines. Known since antiquity as the "game of kings," polo has a long legacy here: The St. Louis Polo Club is the second oldest existing in the country, and the first match benefiting local nonprofits took place here in 1893. This year's match upheld that legacy, with more than 250 guests bringing in $18,000 to benefit the Junior League's community programs.