The detail
Bottom right. A woman in a bustle dress, a man in a top hat — and on a leash, a small monkey. In 1880s Paris a pet monkey was a fashionable oddity, and Seurat added her late, after most of the picture was done. The museum notes she looks as if she was always there. That was the point.
The record
Step back. Every figure is built from dots of separate colour that your eye mixes at a distance. Seurat wanted a modern Sunday to feel as still as a Greek frieze — and he painted the border of dots himself, years later, to hold it.
The line to keep
Dozens of people, three dogs, one monkey — and not a single face turned toward you.