If you associate Puerto Rico's capital with the colonial streets of Old San Juan, then you know only part of the picture. San Juan is a major metropolis, radiating out from the bay on the Atlantic Ocean that was discovered by Juan Ponce de León. More than a third of the island's 4 million citizens proudly call themselves sanjuaneros. The city may be rooted in the past, but it has its eye on the future. Locals go about their business surrounded by colonial architecture and towering modern structures.