In 1915, the Panama Pacific International Exposition in San Francisco was held, celebrating the completion of the Panama Canal.

The Expo showcased the latest innovations, drawing millions of visitors from across the globe. In commemoration of the historic event, A set of four stamps were reissued, each one illustrating historic scenes of Panama and San Francisco.

The most valuable being the 10 cent issue, which has a catalog value of 675 in 2024. The stamp features the Spanish missionaries, Junípero Serra and Gaspar de Portolá, who were pivotal in establishing missions along the California coast during the 18th century. These missions were vital in shaping the landscape of early California.

In fact, the majority of coastal city names in California are of Spanish origin, such as San Jose, Los Angeles, San Diego, Santa Barbara, and of course San Francisco.