Ballpark

Puzzle #21 · 10 October 2026

The five questions from that day's Ballpark, each with its answer, the fact behind it and a link to the source. Rather play it first? It is in the archive.

1. How thick is a sheet of paper, in nanometers, according to the US National Nanotechnology Initiative?

100,000 nanometers

About 100,000 nanometers. A human hair is 80,000 to 100,000 nm wide, while a strand of DNA is just 2.5 nm across. Source

Image: Pratishkhedekar · CC BY-SA 4.0, cropped

2. About how many athletes competed at the Paris 2024 Olympics?

10,500 athletes

About 10,500, with as many women as men, a first for the Olympics. Source

Image: Daieuxetdailleurs · CC BY 4.0, cropped

3. How many items were in the Library of Congress collections in fiscal year 2023?

178M items

More than 178.2 million items, including over 25.77 million catalogued books, in some 470 languages. Source

Image: Carol M. Highsmith · Public domain

4. How deep is the deepest point in the ocean?

10,935 meters

Challenger Deep, ~10,935 m. Everest would fit with room to spare. Source

Image: U.S. Navy · Public domain

5. How many bottles of Champagne were shipped worldwide in 2023, according to the region's trade body?

299M bottles

299 million bottles, down 8.2% on 2022. France took 127 million; the 172 million exported made up more than 57% of the total. Source

Image: JensKunstfreund · CC BY-SA 4.0, cropped