Switzerland quietly carved a massive underground city beneath its mountains—and most people have no idea

When Marco stepped off the train at Göschenen station last Tuesday morning, he expected to see daylight. Instead, he found himself 800 meters below the Swiss Alps, surrounded by the hum of ventilation systems and the distant rumble of freight trains passing through adjacent tunnels. As a maintenance engineer for Swiss Federal Railways, he spends most workdays in what locals call “the city beneath the mountains” – a sprawling network of passages, control rooms, and emergency stations that most travelers never see.

“People think we just drilled a hole through the rock,” Marco says, adjusting his hard hat. “But down here, we’ve built an entire world.”

He’s not exaggerating. What Switzerland has accomplished over the past three decades represents one of the most ambitious underground construction projects in modern history, quietly creating a swiss underground infrastructure that rivals the complexity of major metropolitan areas.

The Alps became Switzerland’s basement

Switzerland doesn’t advertise its underground empire, but the numbers tell an extraordinary story. Since the 1990s, the country has carved more than 2,000 kilometers of tunnels through solid rock – enough underground passages to stretch from Zurich to Rome and back again.

The crown jewel remains the Gotthard Base Tunnel, which opened in 2016 after 17 years of construction. At 57 kilometers long, it’s the world’s longest railway tunnel, boring straight through the heart of the Alps at depths reaching 2,300 meters below the surface.

“We removed enough rock to build three Great Pyramids of Giza,” explains Dr. Sarah Weber, a geological engineer who worked on the project. “But instead of building up, we built into the mountain itself.”

The scale becomes clearer when you consider what surrounds that main tunnel. Emergency escape galleries run parallel to the main tubes. Ventilation shafts climb toward the surface like giant chimneys. Access tunnels branch off to maintenance areas, equipment rooms, and underground substations that power the entire system.

More than trains: Switzerland’s underground city

The swiss underground infrastructure extends far beyond rail transport. Here’s what lies beneath Switzerland’s postcard-perfect landscape:

The Gotthard system alone includes 152 kilometers of secondary tunnels supporting the main rail line. Add the parallel road tunnels, emergency passages, and service corridors, and you’re looking at an underground network that spans more linear distance than many major cities cover above ground.

• Control rooms monitoring train traffic across multiple tunnel systems
• Underground maintenance workshops larger than aircraft hangars
• Emergency stations equipped with medical facilities and communication centers
• Ventilation systems moving enough air to supply a town of 50,000 people
• Underground reservoirs storing millions of liters of water for firefighting

“We joke that if you mapped all our tunnels and put them on the surface, you’d have something the size of Basel,” says Klaus Müller, a project manager with Switzerland’s Federal Roads Office. “Except instead of streets and buildings, it’s all carved from solid rock.”

Why Switzerland went underground

Geography forced Switzerland’s hand, but efficiency sealed the deal. Squeezed between major European markets, with 60% of its territory covered by mountains, Switzerland faced a simple choice: find ways through the Alps or watch trade routes bypass the country entirely.

Traditional mountain passes meant slow, winding roads vulnerable to weather. Avalanches could shut down crucial connections for days. Steep grades limited freight capacity and increased travel times.

The underground solution eliminated these problems while delivering unexpected benefits. Tunnels maintain consistent temperatures year-round. They’re immune to weather disruptions. They preserve the scenic mountain landscapes that drive Switzerland’s tourism industry.

“Our customers don’t want to see industrial infrastructure cutting across pristine valleys,” explains Anna Rothenberger, a transportation planner with the Swiss Federal Office of Transport. “Underground, we can move massive amounts of cargo and passengers without touching the postcard views that define our country.”

The human impact of living above a hidden city

For Swiss residents, the underground infrastructure has transformed daily life in ways both obvious and subtle. Commute times between major cities have dropped dramatically. The Gotthard Base Tunnel cut travel time from Zurich to Milan by an hour, making cross-border business meetings routine rather than day-long expeditions.

Freight transport shifted underground has reduced truck traffic on mountain highways by 30%. Villages that once endured constant heavy vehicle traffic now enjoy quieter streets and cleaner air. Property values in formerly noisy areas have risen as the rumble of passing trucks disappeared underground.

The construction process itself created thousands of jobs in rural mountain communities. Towns like Sedrun and Faido, previously known mainly to hikers and skiers, became industrial centers during tunnel construction. Local restaurants, hotels, and service businesses thrived as thousands of workers spent years drilling through the surrounding peaks.

“My father ran a small café that barely survived on tourist traffic,” says Maria Joller, who owns a hotel in Göschenen. “During tunnel construction, we hosted engineers from around the world. Now with the operational tunnels, we get visitors who come specifically to tour the underground installations.”

Emergency preparedness has also transformed. The tunnel systems include sophisticated rescue capabilities that extend protection to surface communities. Underground water reserves and emergency shelters provide backup resources during natural disasters or extreme weather events.

FAQs

How long did it take to build Switzerland’s major underground infrastructure?
The current phase of major tunnel construction began in the 1990s and continues today, with the Gotthard Base Tunnel taking 17 years alone and the entire network representing nearly 30 years of continuous work.

Can regular people visit these underground tunnels?
Most operational tunnels are restricted to trains and authorized vehicles, but Switzerland offers guided tours of some facilities and has visitor centers explaining the engineering achievements.

How much did this underground network cost?
The Gotthard Base Tunnel alone cost approximately 12 billion Swiss francs, with the entire swiss underground infrastructure representing investments exceeding 50 billion francs over three decades.

Are there plans for more underground construction in Switzerland?
Yes, Switzerland continues expanding its underground network with projects like the Ceneri Base Tunnel and planned connections to neighboring countries’ high-speed rail systems.

How do they maintain air quality in such long tunnels?
Sophisticated ventilation systems pump fresh air through the tunnels continuously, with backup systems and emergency protocols ensuring safe air quality at all times.

What happens if there’s an emergency in these deep tunnels?
Each major tunnel includes parallel emergency galleries, rescue stations every few kilometers, direct communication systems, and dedicated emergency response teams trained specifically for underground incidents.