Even though each region in mexico celebrates day of the dead differently, what are things that they do have in common.

Each region in mexico has its particular way of celebrating the day of the dead.  They use different and local elements to celebrate it.  One thing in common in all of the regions is the use of an altar called "altar de muertos".  The decoration of graves is also a common practice.  In the 1930s during Lazaro Cardenas government, November 1 and 2 was the date set for all Mexican regions to celebrate the day of the dead.  

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.