College student siting alone in lecture hall with head in hands

Teacher in empty classroom

Businessman in open plan office

Businessman standing at window in conference room

Businessman looking out window

Businessman standing in conference room

Businessman standing at conference room window

Businessman standing in empty conference room

Woman at table with birthday cake looking away wistfully

Woman sitting alone in restaurant, looking at cell phone

Woman sitting at table alone with anniversary cake, covering eyes

Well dressed young man at bar

Gibbon

Girl sitting and writing

Coins inside washing machine

Boy standing alone on dock at lake

Boy holding arrows

Boy standing alone on dock at lake

Tree in winter at dusk

Young woman reading a letter, Shanghai, China, Asia

Young woman in a cafe, Shanghai, China, Asia

White game piece in ring with heart cut-out, symbolic for being single

Young Gray Seal (Halichoerus grypus) cub alone on a beach, Heligoland, Schleswig-Holstein, Germany,

Baby Lying on Back