Indian schoolchildren attending school at Doeli in Sawai Madhopur, Rajasthan, Northern India

Long-beaked common dolphin pod (Delphinus capensis) encountered in the southern Gulf of California (Sea of Cortez), Baja California Sur, Mexico

Long-beaked common dolphin pod (Delphinus capensis) encountered in the southern Gulf of California (Sea of Cortez), Baja California Sur, Mexico

Long-beaked common dolphin pod (Delphinus capensis) encountered in the southern Gulf of California (Sea of Cortez), Baja California Sur, Mexico

Golden sweepers, Parapriacanthus ransonneti. This species is often found in thick schools in dark reef recesses. Buyat Bay, North Sulawesi, Indonesia, Pacific Ocean.

Striped catfish, Plotosus lineatus. This species is often found in tight schools feeding on tiny prey in the sand and rubble. Buyat Bay, North Sulawesi, Indonesia, Pacific Ocean.

Long-beaked common dolphin pod (Delphinus capensis) encountered in the southern Gulf of California (Sea of Cortez), Baja California Sur, Mexico

Long-beaked common dolphin pod (Delphinus capensis) encountered in the southern Gulf of California (Sea of Cortez), Baja California Sur, Mexico

A smoke free sign outside Ribblesdale School in Clitheroe, Lancashire, England, United Kingdom, Europe

Long-beaked common dolphin pod (Delphinus capensis) encountered in the southern Gulf of California (Sea of Cortez), Baja California Sur, Mexico

Maypole with insignias painted by Waldorf School pupils, May celebration, Free Waldorf School at Illerblick, Ulm, Baden-Wuerttemberg, Germany, Europe

Library of the Free University of Berlin, called the Berlin Brain, by architect Sir Norman Foster, Berlin-Dahlem, Berlin, Germany, Europe

Skiing school, ski lessons for children, skiers, ski slope, Lech am Arlberg, Vorarlberg, Austria, Europe

Malaysia, Sipidan, Green Sea Turtle (Chelonia mydas) with schooling fish.

Malaysia, Mabul Island, Green Sea Turtle (Chelonia mydas) swimming with schooling jacks