Hidden among pine-covered hills, this observatory is home to the world's largest radar-radio telescope. Operated by the National Astronomy and Ionosphere Center of Cornell University, the 20-acre dish lies in a 563-foot-deep sinkhole in the karst landscape. If the 600-ton platform hovering eerily over the dish looks familiar, it may from the movie Contact. You can walk around the viewing platform and explore two levels of interactive exhibits on planetary systems, meteors, and weather phenomena in the visitor center. There's also a gift shop. Note that the trail leading to the observatory is extremely steep. Those with difficulty walking or a medical condition can ask at the gate about a courtesy shuttle.