In the heart of Spain’s capital, Sobrino de Botín holds a coveted Guinness World Record as the world’s oldest restaurant. But on the outskirts of Madrid, a rustic tavern makes a bold claim.

Kaia, a new restaurant in the South End known for its Aegean coastal cuisine, was named one of the best new restaurants in the world. Danielle Parhizkaran/Globe Staff. By Katelyn Umholtz.