Issued in 1975, this $1.50 airmail stamp commemorates the 650th anniversary of the founding of Tenochtitlán (1325). The design features the historic coat of arms of Mexico City, granted by the Spanish Crown, depicting a fortified tower guarded by lions, with canals symbolizing the city’s origins. Inscribed “Muy Noble e Insigne, Muy Leal e Imperial Ciudad de México” (Very Noble, Distinguished, Loyal and Imperial City of Mexico), it highlights the colonial-era recognition of the city’s importance. A significant issue for collectors of Mexican history, heraldry, and airmail themes.