Off the coast of Susami, Japan, divers post over a thousand waterproof postcards a year into a real mailbox on the seafloor.
Installed in 1999 to celebrate a regional expo, this Guinness World Record mailbox sits 10 meters underwater. Local postal staff scuba dive regularly to collect and deliver the plastic-coated mail.
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Quick Guess: How deep underwater is Susami's working Guinness-record mailbox located?
Verified Answer: 10 meters
Quiz Question: How deep underwater is Susami's working Guinness-record mailbox located?
Correct Answer: 10 meters
Divers swim 10 meters down to drop waterproof postcards that staff regularly collect.
Estimated near 310 decibels, the 1883 eruption of Krakatoa was heard 4,800 km away in Rodrigues Island and circled Earth’s barometers seven times in opposing waves.
Deserts are defined by scarce precipitation, not scorching heat. Covering 14.2 million km² with under 200 mm of annual moisture, Antarctica is Earth’s largest desert.
The full chemical name of the giant human protein 'Titin' contains an astonishing 189,819 letters.
Pitch shatters like glass under a hammer, yet it is a fluid 230 billion times more viscous than water—dripping only 9 times inside its University of Queensland funnel.