Time Capsules from the 1939 and 1964 World's Fairs
Queens, New York
A round capstone, set in the middle of a small circular plaza, marks the resting-place of two time capsules, buried in the "Immortal Well" by the Westinghouse Electric Corporation -- one on September 23, 1938 (the first time capsule ever), and the second on October 10, 1965. They were conceived as modern successors to old-fashioned cornerstones, and were packed with artifacts such as a slide rule (1938) and a Beatles record (1965).
The capsules themselves, 50 feet underground, have remained safe since their burial, although the capstone has occasionally been vandalized with graffiti. Some time capsule fans fret that global warming will leave this spot 30 feet underwater in 5,000 years (which is how long the capsules are supposed to remain buried). This will make them difficult to spot in the 70th century.
Westinghouse engineers designed the capsules to be corrosion- and leak-proof, so we'll just have to hope that someone surfing the Web on their smartphone in the year 6938 will read this page and dig them up.