A Gothic ruin in the middle of the East River

While most visitors to New York focus on Times Square or Central Park, very few venture to Roosevelt Island, a narrow strip of land in the East River that is home to one of the city's best-kept secrets: the ruins of Smallpox Hospital. This abandoned building, built in 1856 in the neo-Gothic style, was the first hospital dedicated to the treatment of smallpox in the U.S., and today is a ghostly, ivy-covered structure that looks like something out of a Gothic novel.

Although the interior is closed to the public for security, the exterior is accessible and offers one of the most dramatic views of Manhattan, with the skyline in the background. The contrast between the decrepit ruin and the modern skyscrapers is surreal. In addition, the island itself is a haven of peace, with pedestrian walkways, quiet parks and an aerial streetcar that offers spectacular (and free) panoramic views of the city.

If you are looking for a dark and mysterious side of New York, away from the tourist traps, this place will fascinate you. It is especially striking at sunset, when the shadows lengthen the silhouettes of the ruins and the city skyline is illuminated in the background.