FIRST DAY ISSUE STAMP ENVELOPES - LOT OF 50

Lot of 50 commemorative first day issue stamp envelopes dating from the 1950s and 1960s with themes including:

• Honoring the American flag (1960).
• 100th anniversary of the Pony Express (1960).
• Commemorating the International Winter Sports Games (1960).
• 150th anniversary of the Louisiana Purchase (1953).
• Commemorating the fifth World Forestry Congress (1960).