Answer:

POLO

Answer	Crossword Clue
POLO	Sport with mounts and mallets
POLO	Prince Charles' sport
POLO	Traveler to Cathay

POLO	Game of chukkers
POLO	Game played on horse-back
POLO	Water sport
POLO	Game with chukkers
POLO	Marco ...
POLO	Lauren's brand
POLO	Game similar to buzkashi, but played with a ball instead of a dead goat
POLO	Shirt with a collar that might be popped

POLO	Type of shirt that might have a popped collar
POLO	Sport of princes
POLO	Game played in chukkers
POLO	Horsemen's game
POLO	Game marked by chukkers
POLO	Game with mallets
POLO	Chukker game
POLO	Horse play?

POLO	Sport played with mallets
POLO	Sport with mallets
POLO	Sport not seen in the Olympics since 1936
POLO	Game with four-player teams
POLO	Olympic sport until 1936
POLO	Sport that originated in Persia
POLO	His travelogue never mentions the Great Wall of China, oddly
POLO	Explorer who charmed Kublai Khan

POLO	Game played on a 300-yard-long field
POLO	Noted traveler
POLO	Company whose logo includes a horse
POLO	Company with a horse in its logo
POLO	Traveler Marco
POLO	Game with horses
POLO	Casual shirt
POLO	Equestrian sport

POLO	Game on horseback
POLO	Prince Charles's pastime
POLO	Silk Road traveler
POLO	Traveler of the 13th and 14th centuries
POLO	Casual top