Oldest mathematical puzzle • dating from 1650 B.C..

As I was going to St. Ives,
I met a man with seven wives.
Every wife had seven sacks,
and every sack had seven cats.
Kitten, cats, sacks and wives,
How many were going to St. Ives?

Most Refractory Substance • Tantalum carbide TaC_0.88 melting at 3,990° C.

- The Guiness Book of Records 1991