On October 21, 1687, Nikolaus I Bernoulli was born in Basel. He was a Swiss mathematician from the Bernoulli family who studied at the University of Basel and later held a chair in logic there, contributing to probability theory and the St. Petersburg Paradox. See wikipedia for more information.

On October 21, 1883, John Nevins Andrews died. He was a co-founder and first official missionary of the Seventh-day Adventist Church, and he is buried in Basel, where he also helped establish a publishing house in Switzerland. See wikipedia for more information.