SEATTLE — Caden Robinson, a 21-year-old college student, said he might not have stood in line for three hours to buy legal recreational marijuana when the first retail sales began here on Tuesday if his parents had not suggested it.

“My dad said I should come,” said Mr. Robinson, a chemistry and chemical engineering major at the University of Puget Sound. “ ‘Go make history,’ ” he said, quoting his father.

His friend Mark Rupprecht, 33, standing shirtless with other prospective buyers under a blazing sun, in a line that eventually grew to include several hundred people, said the sense of history, being part of a symbolic, turning-point moment, was powerful for him, too. “Something to tell my grandkids,” said Mr. Rupprecht, a bartender.

Washington’s experiment with licensed, legal recreational marijuana began tentatively in a handful of places around the state on Tuesday, with limited supplies — because licensed growers have not had time to bring in a full crop, certified by the state to be Washington-grown — but with great enthusiasm and hoopla in the places where the sales occurred.