If Memorial Day is the unofficial start of summer, the Pimm's Cup may be the season's unofficial cocktail. Unlike a lot of other warm weather drinks, this one didn't originate in some sunny, tropical locale—it actually hails from England. Which make sense. Cool and crisp, with a citrusy, herbaceous tang and served over tinkling cubes of ice, this gentlemanly elixir is as restrained as it is refreshing. The tea-hued gin-based liquor Pimm's No. 1 Cup is the foundation of the eponymous cocktail. It was invented in the 1840s by James Pimm, the owner of a London oyster bar, who marketed it as a health tonic. And well, if you need something to revive you on a hot summer afternoon, this sweetly spiced, low-alcohol tipple will cure what ails you.