Two pigeons standing next to each other on the ground surrounded by…

Molecular model of a peptide molecule

Molecular model of a hydrogen atom

Aerial view of a city with a large body of water

Open book with Chinese writing on it

Painting of a rocky hillside with a house in the distance

Black and white photo of a man wearing a coat

Black and white engraving of a man in a military uniform

Poster of a map of South America with yellow fever zones highlighted