Light rail vehicle leaves the West Lake Street Station for the first time.

This morning Metro Transit towed a light rail vehicle through the line for the first time doing basic clearance testing. Construction on the green line extension began in 2018 and is set to open to passengers in 2027.

First light rail vehicle through the Kenilworth tunnel.

This morning Metro Transit towed a light rail vehicle through the line for the first time doing basic clearance testing. Construction on the green line extension began in 2018 and is set to open to passengers in 2027.

"Fuck The System" written on a bike trail near downtown Minneapolis.

A tunnel boring machine (TBM) rests near the banks of the Mississippi River, staged for the start of a subsurface water main tunnel project. The machine’s circular cutting head and support equipment are visible beside heavy lifting cranes, part of a major infrastructure effort to modernize the city’s underground water distribution system

An aerial view captures the excavation shaft for a massive water main tunnel beneath the Mississippi River. The reinforced concrete cylinder serves as the launch point for a tunnel boring machine, visible nearby, which will cut through layers of limestone and shale to create a new conduit linking the city’s water systems. The project represents a critical upgrade to regional infrastructure, designed to improve reliability and resilience while accommodating future demand across Minneapolis and St. Paul.

The curved platform of a Chicago Transit Authority Blue Line station reveals the utilitarian design of the city’s subway infrastructure, part of the Milwaukee–Dearborn subway opened in 1951. The tunnel’s tiled blue panels and low arched ceiling reflect the postwar engineering era that brought rapid transit beneath the Loop and the West Side, connecting O’Hare International Airport to downtown. Despite its age, this corridor remains a vital artery in Chicago’s daily commuter network, a symbol of mid-century urban mobility still in constant motion beneath the city streets.

The shaft being made that will bring a tunnel boring machine to bore a tunnel under the Mississippi River for a water main.

A man walks down a long hallway in the New York City Subway system.

A dimly lit stairway leads down into a New York City subway station on Sunday, Sept. 14, 2025. Aging infrastructure and exposed piping are visible along the tiled walls.

Cramer Tunnel in Cramer Minnesota. The tunnel operated from 1957 to 2001. The tunnel connect the LTV Steel taconite plant in Hoyt Lakes to the ore dock at Taconite Harbor.

Carved directly through a narrow granite spire in the Black Hills, the Needles Eye Tunnel stands as one of South Dakota’s most distinctive engineering feats. Completed in 1922 as part of the Needles Highway (SD 87), the one-lane tunnel measures just 8 feet 4 inches wide and 11 feet 3 inches high, requiring careful navigation by passing vehicles. Its name comes from the adjacent rock formation, where centuries of wind and water erosion sculpted a sharp, needle-like opening. Surrounded by dense ponderosa pine forest and sheer stone walls, this section of the highway offers one of the most dramatic mountain drives in the American Midwest, linking the spire formations of Custer State Park with the scenic byways leading toward Sylvan Lake and Mount Rushmore.

The Needles of the Black Hills of South Dakota are a region of eroded granite pillars, towers, and spires within Custer State Park. Popular with rock climbers and tourists alike, the Needles are accessed from the Needles Highway, which is a part of Sylvan Lake Road (SD 87/89). The Cathedral Spires and Limber Pine Natural Area, a 637-acre portion of the Needles containing six ridges of pillars as well as a disjunct stand of limber pine, was designated a National Natural Landmark in 1976. -- Wikipedia

A surviving pressure control and alarm panel from the Clapham South deep-level shelter, part of London’s extensive subterranean civil defence network built during World War II. Marked for Shafts 9 and 10 — Balham Hill and Clapham Common — this steel and cast-iron tunnel section reflects the industrial engineering that underpinned the capital’s wartime infrastructure.

The shelter, completed in 1942, was constructed 36 meters below ground to house up to 8,000 civilians during Luftwaffe air raids. Panels like this one were integral to the shelter’s life-support and safety systems, monitoring air pressure, fire mains, and CO₂ levels to maintain breathable air and protect against smoke or gas intrusion. The utilitarian design, reinforced bolted segments, and residual wartime paintwork remain as tangible reminders of Britain’s wartime engineering precision and the resilience of Londoners forced to seek refuge deep beneath the city’s streets.

A wartime directional sign inside the Clapham North deep-level shelter, one of eight civilian bunkers built beneath the London Underground during World War II. Constructed in 1940–1942 and located over 100 feet below ground, these tunnels were designed to protect thousands of civilians from German air raids during the Blitz. The painted wooden sign directs occupants toward vital amenities — medical aid, lavatories, and the canteen — illustrating the organized, self-contained nature of these subterranean refuges.

Rows of bunk beds once lined these tunnels, each assigned a number for families or individuals. The close quarters, reinforced concrete linings, and utilitarian signage evoke the claustrophobic yet crucial life-saving environment that became a hallmark of London’s wartime resilience. Today, Clapham North’s deep-level shelter stands preserved as a powerful reminder of the capital’s civil defence network and the endurance of its citizens under bombardment.

A British Civil Defence leaflet issued in July 1939, weeks before the outbreak of World War II, titled “Some Things You Should Know if War Should Come.” Distributed by the Lord Privy Seal’s Office, it was the first in a series of public information pamphlets intended to prepare civilians for air raids, blackout regulations, and the use of gas masks. The leaflet’s sober directive — “Read this and keep it carefully. You may need it.” — reflects the government’s attempt to balance reassurance with realism as Europe edged toward conflict.

Millions of these leaflets were delivered to homes across Britain as part of an unprecedented civil preparedness campaign. Surviving examples like this one, often yellowed and worn with age, stand as historical evidence of the anxious months before September 1939, when the nation braced for the total war that would soon arrive.

A deep-level shelter tunnel beneath Clapham North, one of eight such subterranean structures built during World War II as civilian air-raid refuges along the London Underground. Constructed between 1940 and 1942, these reinforced cylindrical passages were designed to house up to 8,000 people during bombing raids, each equipped with bunks, lavatories, and medical posts. The distinctive bolted cast-iron lining — a hallmark of wartime tunnel construction — remains intact, illuminated by fluorescent fixtures added decades later.

After the war, the tunnels were repurposed for various uses, including temporary accommodation for Commonwealth immigrants and later as part of London Transport’s secure archival storage. Today, the Clapham North tunnels represent one of the most intact examples of London’s wartime civil engineering — a hidden layer beneath the active Northern Line that reveals the city’s dual legacy of transit innovation and wartime resilience.

A view inside one of the distinctive spiral staircases of Clapham North Underground Station on the Northern Line, part of London’s deep-level tube network completed in the 1920s. The cast-iron stairwell descends nearly 120 feet below ground, wrapping tightly around a central ventilation column used to regulate air pressure and temperature within the tunnels. The staircase, equipped with yellow anti-slip edges and a steel handrail, was designed as an emergency exit and maintenance access route for the deep-bore platforms below.

Stations like Clapham North, along with its twin Clapham Common, are known for their rare narrow island platforms and compact circular shafts — relics of early tube engineering when space and construction methods were limited. The robust riveted metalwork and industrial geometry of the stairwell reflect the period’s emphasis on function and endurance, forming part of London’s complex subterranean infrastructure still in use more than a century later.

Lowry Hill Tunnel in downtown Minneapolis.