See photos of the world's largest ball of stamps at Atlas Obscura. This big bertha weighs nearly 600 pounds and has a 32-inch diameter.
So how many stamps are in this thing, you may ask? According to atlas obscura, over 4 million canceled stamps are packed together into this sphere. Woah!
The stamp ball had a simple beginning, and then grew and grew; "The origins of this quirky anomaly date back to 1953, when a group known as the Boys Town Stamp Collecting Club started to consolidate the less-valuable stamps using a golf ball as a base." The ball continued to increase in size until 1955, when it was recognized by Ripley's Believe it or Not, and put on display.
I never want the ball to get destroyed, but I wonder what it would look like when cut open. It would be super cool if it were possible to take an x-ray photograph of its layers.