Madrid

Sobrino de Botin, according to the Guinness World Records, the oldest restaurant in the world, is located in Madrid.

An excerpt from the article 17 facts about Madrid
Established by a Frenchman Jean Botin and his wife, who fell in love with the local cuisine while traveling around Span, the restaurant has been operating continuously since 1727. Apparently, the dishes served in the restaurant are prepared according to the original eighteenth-century recipes and the fire in the tabernacle also burned constantly since its opening. Francisco Goya worked at this restaurant while he waited for acceptance at the Royal Academy of Fine Arts.