In 1974, Philip Johnson’s Glass House was 25 years old. The Architectural League of New York celebrated with a birthday picnic on September 22 of that year, with photos documenting not only the house, but the grounds and other Johnson-designed structures.

Not much has changed but the people. All you have to do is identify as many guests as possible from the architectural community in the following photos to win the prize.

The rules
1. Identifying Philip Johnson (the host) doesn’t count.
2. No repeat identifications are allowed: if the same person appears in two photos, only one identification qualifies.
3. The entrant who can identify the most people wins. In case of a tie, the first entry received wins.
4. The contest ends on August 15.
5. No employees of the McGraw-Hill Companies, (including Architectural Record) or Monacelli Press can enter.