Guanajuato Underground Tunnels Guide

About the Tunnels

Guanajuato is the only city in the world where a significant portion of its traffic flows through underground tunnels that were once river channels. This unique feature arose from necessity: Guanajuato sits in a narrow ravine, and the Guanajuato River that once ran through the city center caused devastating floods for centuries.

In the mid-20th century, engineers diverted the river through a dam system and converted the empty riverbed into a network of underground roadways. Over the decades, additional tunnels were excavated to handle growing traffic. Today, the system includes over 20 kilometers of tunnels that carry both vehicle and pedestrian traffic beneath the city.

The Experience

Walking through the tunnels is surreal. Stone-lined corridors that once carried rushing water now carry cars and buses, with sidewalks for pedestrians. Natural light filters in through openings at intersections, and at certain points you emerge briefly into open-air plazas before ducking back underground.

What You Will See

• The original riverbed tunnel -- The oldest and most atmospheric section, with rough stone walls and arched ceilings
• Vehicle traffic -- Cars, buses, and trucks sharing the tunnels with pedestrians (use caution)
• Portals and openings -- Points where the tunnels emerge at street level, offering glimpses of the colorful city above
• Connected streets -- Some surface streets connect to tunnel sections, creating a multi-level urban experience

How to Explore

• Walk -- The best way to experience the tunnels is on foot. Enter at the western end near the Alhondiga de Granaditas (a historic granary and museum) and follow the tunnel system through the city center. The walk takes about 30-45 minutes.
• By car or bus -- Driving through the tunnels is part of daily life in Guanajuato. If you arrive by bus, you may pass through them on the way in.
• Guided tour -- Some walking tours of Guanajuato include tunnel exploration with historical context
• Callejoneadas -- The evening musical tours sometimes pass through tunnel sections

Visiting Tips

• Watch for traffic -- The tunnels are functioning roads. Stay on sidewalks and be aware of vehicles, especially at intersections.
• Not claustrophobic-friendly -- Some sections are narrow. If enclosed spaces bother you, stick to the wider, well-lit main tunnels.
• Photography -- The tunnels create interesting light effects, especially where natural light enters. A phone camera works fine.
• Orientation -- It is easy to get disoriented underground. Carry a map or use GPS. When in doubt, follow the main tunnel toward the center of town.

History

The flooding problem in Guanajuato was severe. The river would swell during rainy season, inundating the narrow streets. Major floods in the 18th and 19th centuries caused significant damage and loss of life. The dam and tunnel conversion project in the 1960s finally solved the problem while creating one of the world's most unusual urban features.

Getting There

The tunnels are integrated into Guanajuato's street system. The main entrance points are near the Alhondiga de Granaditas on the west side and near the Jardin de la Union in the city center. You cannot miss them -- if you walk or drive through Guanajuato, you will inevitably encounter them.

Plan Your Visit

The tunnels are part of any visit to Guanajuato and feature in the Colonial Cities 7-Day itinerary. Combine tunnel exploration with a photography tour to capture this uniquely surreal urban landscape.