Considered the oldest European-founded city in the Americas, Santo Domingo was founded by Christopher Columbus’ brother Bartholomew in 1496. The city grew quickly in importance, and the first Spanish governor of the Indies, Nicolás de Ovando, took up residence in 1502. The colonial part of the city, declared a World Heritage site by UNESCO in 1990, is still home to several important and interesting colonial-era buildings.
Santo Domingo’s importance waned over the next couple of centuries, as it was vulnerable to piracy and mainland cities became wealthier. When French slaves in Haiti rebelled in 1822, they even managed to take over the present-day Dominican Republic for a period of 22 years.
The gap between the rich and poor in the city is a wide one. Visitors will see elegant homes, fancy high-rises and modern cars as well as shacks and shantytowns. The crime rate has been up in recent years, in part because of a recession in the economy.
Visitors who want to check out the old colonial section of town, which is home to several interesting buildings and museums, including the home of Christopher Columbus’ son Diego, known as the Alcázar de Colón. There are several parks, including a zoo. Baseball fans will definitely want to catch a game: Santo Domingo is home to the Leones del Escogido and the Tigres del Licey teams. Many major leaguers play on these teams during the baseball off-season. 
There is good shopping in town if you’re looking for some souvenirs. The Dominican Republic is one of the world’s leading producers of Amber, and you can even check out the Amber Museum on Arz. Meriño 452 in the colonial section. There are fine cigars everywhere, and other locally-made products include rum, coffee, and cocoa. Tourist-trap gift stores sell paintings, t-shirts, pirate stuff (i.e. beer mugs with pirate flags on them), hand-carved African-style masks, and more assorted crap than you could go through in a month. Prices are surprisingly high, but if you need a magnetized bottle opener with a pirate skull on it that says “Dominican Republic”, where else are you going to find one?
Santo Domingo is known for sizzling nightlife, as the locals salsa and meringue the night away. Bring your dancing shoes, but be sure to take care, as tourists can be targets for thieves and scammers.