There has been some concern over the cost of the celebrations Mexico is celebrating the bicentennial of its independence with parties across the country.
However, security is high in many regions, with some towns and cities cancelling or cutting back festivities amid fears of drug cartel violence.
The celebrations mark the 1810 uprising that paved the way for the end of Spanish rule in 1821.
Wednesday’s show of concerts, parades and fireworks in Mexico City is said to be the largest of its kind in Mexico.
But correspondents say the run-up to the events has been marred by accusations of overspending, bad planning and security concerns.
Heavily-armed agents carrying metal detectors are being deployed for the capital’s celebrations and helicopters will provide added security.
More than 100,000 people are expected at the Mexico City events, guarded by more than 14,000 police officers, including snipers on rooftops.
After the massive parade, the climax of the celebrations will be the traditional “grito” (shout of independence) by Mexican President Felipe Calderon, which will be broadcast across the country from the capital’s main square.
The shout is an echo of the battle cry of Catholic priest Miguel Hidalgo, who began the 1810 uprising.
Local leaders and Mexican citizens will cry “Viva Mexico!” in response.
However, the grito cry by the mayor of Ciudad Juarez will come from behind closed doors.
The independence celebrations have included historical re-enactments The city, close to the Texan border, is the centre of the drug-related violence that has left 28,000 people dead in Mexico since 2006.
Guadalupe, east of Ciudad Juarez, has cancelled its celebrations.
Security will also be tight in Morelia, in the president’s home state of Michoacan. Eight people were killed in a grenade attack there on Independence Day in 2008. The central square will be largely closed off.
A number of towns in the northern states of Chihuahua and Tamaulipas, and in Guerrero in the south, have also cancelled festivities.
The BBC’s Julian Miglierini, in Mexico City, says the bill for the celebrations – $230m (£148m) – has caused concern among many Mexicans.
A survey in the Reforma newspaper suggested eight out of 10 Mexico City residents thought too much was being spent.
Given the number of deaths in the drug-related violence, our correspondent says many Mexicans think there is simply not much to celebrate.
On Thursday, foreign heads of state will attend an annual parade on Mexico City’s Reforma avenue and Zocalo square.
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