The railroad across the Isthmus of Tehuantepec, located in southern Mexico, once provided a vital transportation link for shipping between the Atlantic and Pacific Oceans before the Panama Canal was constructed. With the canal undergoing upgrades, the railroad is once again providing that important link. On the southern side of the isthmus is the town of Tehuantepec. Its people are a mixture of Spanish, French and native. The society is primarily a matriarchal one. Fifty miles north is another of the region’s important cities, Oaxaca, the capital of the similarly named state. Just outside the city are the ruins of Monte Albán. One of the most important private collectors of the area’s historic artifacts is renowned artist Diego Rivera.