The Commonwealth of Puerto Rico is a gem for U.S. travelers. You can visit it as easily as any other state in the nation. Puerto Rico was acquired by the United States in 1898 as a result of the Spanish-American War, and Puerto Ricans became U.S. citizens in 1917.  The island’s national historic site in Old San Juan is a must-see with the fortifications which protected the city from land and sea attack. Strolling along the streets of Old San Juan with its vibrant colors, restaurants and bars, makes for a great day, or days, of enjoyment. Venture beyond the city for the island’s beaches, including three bioluminescent bays, and the tropical rainforest, El Junque National Forest.