There is a place in this city where the gap between rich and poor can be seen as clearly as if it were photographed for a tourist post card.
On one side of the Santa Catarina river lies Mexico's wealthiest community, San Pedro Garza Garcia, where luxury is the norm.
The largest shopping mall here brings to mind the US culture of consumption. A couple of women coming out of a store laugh and say how happy they feel after spending $5,000.
Not that there is no shopping on the other side of the river. An old couple here bargain for tomatoes for less than a dollar to cook their dinner. Fruits and vegetables are rare. Most of the non-food merchandise for sale is second hand: clothes, dishes, shoes, tools for newly arrived construction workers who sell their day's labour for less than $10.
A local newspaper shows a picture of two men hanging from a pedestrian bridge on the front page. They were tied, hanged alive and then shot dead in broad day light on a main street.
At the newspaper stand, I flip through a thick magazine where the local elite are portrayed attending their social events.
I was particularly shocked by a small article with a picture of a couple whose 31-year-old son was killed a week earlier, after being kidnapped. The mother smiles, wearing black.
What is happening to this prosperous city - once widely reputed as a symbol of hard-working people and home to many of Mexico's largest multinational companies - is a tragedy.
Business owners who can afford to move their families to the US have relocated to San Antonio and other cities in Texas. The working class, many of whom are not eligible for US visas, have meanwhile been adapting to living in danger, as criminal gangs have been fighting over this territory for years.
But a recent wave of violence indicates things are getting out of balance.
Local journalists and observers explain that the Gulf Cartel, which controlled this territory before the government launched its crackdown on gangs in 2006, has been in confrontation with their former allies, the Zetas.
But since the Zetas have fractured, reportedly due to an internal leadership battle, another group from Sinaloa is making inroads in this city of some four million people. Now there are four heavily armed groups scrambling to control everything from kidnapping to extortion, prostitution and illegal drug sales.
Things are getting out of control, not only in Monterrey, but throughout Mexico. When large criminal organisations become fragmented and start fighting each other, brutality rules, murder becomes an everyday issue. That is the case in Monterrey.
In many neighbourhoods here, people simply don't go out at night.
The City's old district, or barrio viejo, is in decay. The many "For Sale" signs and bullet holes pock-marking the walls of formerly famous venues tell the story: extortion by criminals has increased, often two or even three rival groups would show up to collect their "fee". Many businesses were reportedly forced to sell drugs.
Deals between gangs
Another explosive ingredient in this Molotov cocktail of a city is politics.
Mexicans went to the polls on July 1 to elect a new president and thousands of other public officials, including 15 governors, the entirety of Congress and this city's mayor.
The usual ties kept by organised criminals with politicians have been disrupted by the poll. Mexico is entering once more into this dangerous period between administrations. There are five months between election day and the inauguration of the new president, in which the deals between gangs and their insiders in government and law enforcement fall apart, and the search begins again for new power brokers, new lobbyists and friends in Congress.
Meanwhile, the Wild West rules the city's streets.
Fortunately there are good stories to be told.
One part of Monterrey, Guadalupe, was once the second deadliest municipality in the whole of Mexico, only after the notorious Ciudad Juarez. A former army colonel took over the local police force here and fired every officer, more than 700 men, because they were allegedly working for the Zetas.
He now works with fewer than 300 loyal officers - mostly former army members who live inside barracks, away from potential cartel influence. They kicked the Zetas out of Guadalupe.
Most of these men - and a few women - are driven by faith. They practise their religion and often pray before going out to patrol the rough streets and hillsides of Guadalupe, now a much more pleasant place to live, according to locals.