In 1833 in Vallée de Joux, Switzerland, the young Antoine LeCoultre opened his first atelier. He’d experimented with music boxes before, but now he wanted to be a watchmaker. It took only 11 years for LeCoultre to invent the world’s most precise time-measuring instrument. Cut to 1903, years after Antoine’s death, when his grandson Jacques-David LeCoultre meets the Paris-based watchmaker Edmond Jaeger, famous for trendy, ultra-thin watches. LeCoultre challenged him by creating the world’s thinnest watch, in 1907. The pair started to work in tandem, and technical improvements happened with regularity. Come 1931, when the glass casings on watches worn by polo players were shattering during matches, the company devised a watch that could be temporarily “flipped” or “reversed.” They called it the Reverso. This exhibition at Iron23 tells the fascinating story. Check out the 1931 café in the back, with desserts by the award-winning pastry chef Nina Métayer. —Elena Clavarino