The Mexican flag obviously has had changes along its history until now. There have been a lot of changes, but I´m going to mention the most historically important and representative of them.
For more obvious reasons the first Mexican flag that was considered a representative icon for this country was the one used in the Mexican Independence from Spain. This flag was actually a banner which the priest Miguel Hidalgo y Costilla took from the atrium of the Atotonilco Parish. This banner had an image of the Guadalupe virgin and is currently exhibited in the National Mexican History Museum, in Monterrey.
The next important change of the flag was when José Maria Morelos y Pavón started to use a different flag in the second period of the Independence. This flag had a crowned eagle over a cactus and three letters “V.V.M”, which means in Spanish “Viva la Virgen María”.
The most important change of the flag was when the Trigarante army started to use a flag with the current colors; green, white and red. This army was the one which consumed the Mexican Independence winning the war with Spain. This was first national and official flag of the country considered the image of Mexico by the first Mexican emperor; Agustín de Iturbide. It was made in Iguala, in 1821. This flag is the one considered the predecessor of the current flag because it was the first to use the same colors of the current flag.
Another important fact about the flag is its colors and the figure in the middle of it. The meaning of the colors is really simple. The green means independence, this is obviously the independence from Spain, the red means union; between the European and the American people, and finally the white means religion; and refers to the devote religion for the Catholic Church. This were the first meanings of the colors and actually nowadays the meanings are still the same, but in the Benito Juarez presidency time the meanings changed for a while because of the reformist and lay ideas. In those years the meaning of the white was unity, the red was the national hero’s blood and the green was hope.
Lastly the symbol in the middle of the flag, which is an eagle eating a snake while it’s standing over a nopal was taken from an Aztec code and a legend. The Aztec legend said that the ideal place for the Aztec people to build their city would be revealed by their god; Huitzilopochtli. This place was revealed when they saw an eagle eating a snake over a nopal in the middle of a lake. The Aztecs built their city there. The flag´s symbol was taken from that legend.
As my favorite personal experience with the flag, I would say, it was when I was in the school honor guard and I was the one who to carry it. I would empathize that for a ten year old boy, the flag is too heavy. During a ceremony in the school, I was carrying the flag. In the school ceremonies, the honor guard had to walk around the school path, so when we were turning around, I lost the balance of the flag and pushed the person who was next to me. In that way, I formed a chain and lastly the entire honor guard fell down because of me. Everybody in that ceremony laughed and I was removed from the honor guard.