Flag; South East Asia Treaty Organization (SEATO) stamp first day (machine cancel)
| Image2 | |
| City | Washington |
| State | DC |
| Subject | Organizations |
| Description | Flag; South East Asia Treaty Organization (SEATO) stamp first day (machine cancel) |
| Year | 1960 |
| Month | 5 |
| Day | 31 |
| Color | black |
| Notes |