PANAMA-PACIFIC EXPO Four different designs pay tribute to Vasco Balboa, first European to see the Pacific and the 1914 opening of the Panama Canal. The 5˘ stamp shows the San Francisco’s Golden Gate, site of the Panama Pacific Expo that celebrated the 400th anniversary of Balboa’s discovery. Due to its yellow-orange color, much of the 10˘ stamp’s detail was lost, prompting a dark-orange replacement. Perf. 12 sheets were later strengthened by a change to Perf. 10, making this variety among the scarcest 20th century commemoratives.
