With 1.2 million inhabitants, Santiago de Cuba is the country's second biggest city, located at the far eastern tip of the island. The largest, Havana, could be described as refined (and defined) in a Colonial-style way, with big boulevards, squares and architecture, spread out flat along the sea front; Santiago by contrast is a jumbled mess of streets laid out chaotically on a steep hill side, more reminiscent of Rio de Janeiro, Brazil. Santiago de Cuba has a got a strong Caribbean vibe to it, evident in the people, the food, the history, the nightlife and the culture.
Santiago is also where Cuba's revolution began, and there are monuments and modern-day graffiti all over the city to commemorate the various rebel leaders, including Antonio Maceo, who led the fighting in the Wars of Independence against the Spanish and the Americans, as well as Fidel Castro, who studied at university there. On July 26, 1953, Castro and his small revolutionary army launched an attack on the Cuartel Moncado military barracks. While the incident was a disaster, it laid the foundations for the revolution to come -- and it was there in a show trial that Castro made his famous "History will absolve me" speech.
Founded in 1514, Santiago served as the capital of Cuba for almost 100 years before the Spanish decided to shift it to Havana in 1607. Santiago enjoyed mixed fortunes over the years and became a major trading post for slaves brought from West Africa, Haiti and Jamaica (hence the makeup of its population). Its remoteness means it developed at a slower pace than the rest of the island, with a distinct cultural feel. It also means it is decidedly un-touristy, and you'll find a sometimes startling naivete and warm welcome from the inhabitants.
Santiago also has a strong musical heritage, influenced by these cultures. Cuba's popular national music, Son, originated in Santiago and is best encapsulated by the music of Buena Vista Social Club, a popular music venue in Havana. Santiago also hosts one of the most riotous and legendary Carnivals in this part of the world in July.