It's easy to get overwhelmed in Oaxaca's Benito Juarez market. The space is packed with stands and loud hawkers selling everything from mezcal to swords to live animals. But in the middle of the action lies a refreshing oasis with giant clay pots of horchata and a rainbow of pitchers containing regional aguas frescas. This is Casilda Aguas Regionales, and it's been selling delicious, traditional Oaxacan drinks since 1926.

A large black-and-white portrait of the late Casilda Flores Morales, the founder, watches over the small space. It's no surprise that her business has staying power: Morales came from a family of drink vendors. Her grandparents sold agua de chilacayote—a sweet beverage that combines a local squash with cinnamon, panela, and pineapple—in the city's zócalo starting in 1890. She learned the trade from her mother and aunt before obtaining her own vendor license to set up shop in Benito Juarez in 1926. 

Today, Casilda's successors still offer the family's agua de chilacayote, among many other recipes that have been passed down generation to generation. Besides the sweet squash drink, the stand's other offerings include aguas frescas made with tropical fruits (sapodilla and guanabana are favorites) and a range of flavored horchatas. The most popular variety of the latter is the horchata con tuna, a distinctly Oaxacan style that incorporates syrup from the prickly pear fruit. To make the bubblegum-pink refresher, a vendor at Casilda first scoops the house horchata—made from water, rice, almonds, and cinnamon—out of one of the giant clay pots, then adds a dash of the crimson syrup, a few chunks of cantaloupe, and a sprinkling of pecans. Sweet, cool, and creamy, it's the perfect antidote to a hot, dry day.

As the city finds itself with an increasing number of hyper-chic, modern restaurants and vendors selling imported, imposter crafts, the nearly century-old Casilda is a time capsule just waiting for visitors to take a sip of authentic Oaxacan traditions.