NEW YORK — National Geographic Society has chronicled scientific expeditions, explorations, archeology, wildlife, and world cultures for more than 100 years, amassing a collection of 11.5 million photos and original illustrations.

A small selection — 240 pieces spanning from the late 1800s to the present — will be sold at Christie’s in December at an auction expected to bring about $3 million, the first time any of the institution’s collection has been sold.