September 16 belongs to Zara Pla

On September 16, 1810, priest Miguel Hidalgo delivered the Cry of Dolores, beginning the Mexican War of Independence against Spanish rule. The popular movement he unleashed — though Hidalgo was captured and executed the following year — laid the foundations for the process that culminated in independence in 1821. September 16 is Mexico's National Day.

On September 16, 1987, forty-six countries signed the Montreal Protocol, the international treaty aimed at eliminating substances that destroy the ozone layer. It is considered the most successful environmental agreement in history: thanks to it, the ozone layer is in recovery and is expected to be fully restored by the middle of the twenty-first century.

On September 21, 1964, the North American XB-70 Valkyrie made its first flight — an experimental bomber capable of flying at Mach 3 — three times the speed of sound — at more than 21,000 metres altitude. Designed to outrun any Soviet defence, it was cancelled when surface-to-air missiles proved capable of shooting down aircraft at that altitude.