Cries of "enough" and "long live Mexico" rose up from sea of white-clad demonstrators filling Mexico City's enormous Zocalo square. The protesters held candles twinkling in the darkness as they sang the national anthem before dispersing.
"I've had enough. Kidnapping, corrupt police, a rotten judicial system," said Ricardo Robledo, a 43-year-old music producer who said he had been robbed numerous times. "This may begin a change."
City officials refused to give a crowd estimate, but the Zocalo can hold nearly 100,000 people. Tens of thousands overflowed into the surrounding streets, unable to squeeze into the square. Thousands more protested in cities across the country.
In the capital, Romana Quintera, 72, wore T-shirt with a photograph of her baby grandson, who was kidnapped for ransom five years ago when gunmen burst into her home and killed her niece. Two people imprisoned for the attack have refused to reveal the boy's fate, and Quintera said investigators have given up on the case.
"We're desperate," she said, holding back tears. "We ask authorities with all our heart to be more sensitive. Maybe nothing like this has happened to them, or they would be more sensitive."
Despite the arrest of several drug kingpins, little has improved the ground since the Calderon government began its crackdown.
Homicides have surged as drug cartels battle each other for control of trafficking routes and stage vicious attacks against police nearly each day. In the gang-plagued border state of Chihuahua alone, there have been more than 800 killings this year, double the number during the same period last year.
This week, a dozen headless bodies were found in the Yucatan Peninsula, home to Mexico's most popular beach resort, Cancun.
While impoverished Mexicans stage almost daily strikes and protests, Saturday's marches brought out thousands of middle-class citizens who are often the targets of kidnappings. The protest was inspired by the abduction and murder of the 14-year-old son of a wealthy businessman - a case that provoked an outcry when prosecutors said a police detective was a key participant in the abduction for ransom.
The boy's father, Alejandro Marti, called on top government officials to quit if they could not stem the crime wave. His challenge became a rally cry at the march, where many held up signs with his words: "If you can't, resign."
The first to arrive for the Mexico City protest was the family of 24-year-old Monica Alejandrina Ramirez, who was kidnapped on in 2004 and has not been heard from since.
Hours before the march began, the family stood silently beneath the independence monument, holding up large banners with her picture. Some colleagues of her mother, a circus performer, walked on stilts and wore clown wigs to help draw attention.
"The most frustrating thing has been the indolence of many of the authorities, their insensitivity," said her father, Manuel Ramirez Juarez, a family doctor. "I have often asked myself, why? Why me? Why my daughter?"
Having staked his presidency on improving security, Calderon responded to the rising anger by summoning governors and mayors to a national security meeting, drawing up a a 74-point anti-crime plan.
It included plans for better police recruiting and oversight systems, as well as an anti-kidnapping strategy within six months. The Defense Department promised to equip police with more powerful automatic weapons.
Calderon has urged patience, warning that rooting out drug gangs and bringing security to the streets would not happen by decree.
Neither will cleaning up and bolstering Mexico's police.
In some northern towns, officers complain of having to share guns, and many have quit in terror after seeing colleagues killed in front of their homes.
More than half of Mexico's state and municipal police officers have only a primary education, making it difficult for them to aspire to the highest ranks and salaries. Many are tempted to join the payrolls of criminal gangs.
"When you go out, you go with fear - are you going to make it home or not?" said Almicar Polanco, 42, marching with about 2,000 others in the border city of Tijuana, across from San Diego. He clutched a flier with a faded picture of his father-in-law, kidnapped two years earlier and missing ever since.
Associated Press writers Niko Price in Mexico City and Dan Keane in Tijuana contributed to this story.