Long gone are the days when heaps of green vanilla pods were drawn into town by mules and laid out on woven mats to dry in the sun, perfuming the streets before being packed up and sold abroad. In this corner of eastern Mexico, known as “the city that perfumed the world,” the aromatic spice once dominated daily life and contributed to Mexico becoming the world’s leading supplier of vanilla more than a century ago. Markets have long since shifted and artificial vanilla is now the global norm. But in Papantla, a city in Veracruz state where the spice is still strongly tied to people’s identity, …