The colorful, confusing history of the two 10th Avenue Bridges in Minneapolis

There aren't a lot of ruins in Minneapolis. Most old structures are demolished before they've had a chance to molder in picturesque fashion.

But if you walk across the Stone Arch Bridge, you'll notice a massive stone pier jutting up from the Mississippi River near its eastern shore. If you look closely, you can spot the remains of a second pier marooned on land near the University of Minnesota's power plant off 6th Avenue SE.

The piers were once part of the first 10th Avenue Bridge, which, by an oddity of the city's numerical street system, was in fact about four blocks upriver from today's 10th Avenue Bridge.

The disconnect stems from the fact that the old bridge extended from 10th Avenue S. in downtown, whereas the current bridge takes its name from 10th Avenue SE. on the other side of the river.

No city has more Mississippi River bridges than Minneapolis, but there was a time in the early days of the city when just one vehicular bridge crossed the river, at Hennepin Avenue. This wasn't the case for long, however.

In 1872, when Minneapolis merged with the old village of St. Anthony on the east side of the Mississippi, the deal included an agreement to build two new bridges to better connect the two sides of the newly expanded city.

The so-called Upper Bridge at Plymouth Avenue, completed in 1873, was a wooden structure that lasted less than a decade. By contrast, the 1874 Lower Bridge at 10th Avenue S. was a 1,100-foot-long iron structure that would stand, albeit a bit shakily toward the end, for almost 70 years.

The bridge was a remarkably airy structure, its narrow roadway running atop a web of iron trusses. It was often photographed next to the Stone Arch Bridge, and the two spans formed a stark contrast. Whereas the Stone Arch Bridge conveys a sense of mass and power, the 10th Avenue Bridge looked delicate and rather precarious, its thin railings offering little protection to the unwary pedestrian or driver.

Those minimalist railings must have made a walk across the bridge a vertiginous experience as the river rushed along 75 feet below. Unfortunately, the span attracted so many jumpers that it became known as "suicide bridge." Despite this unhappy state of affairs, it appears that the city never took steps to fortify the easily surmountable railings.

The bridge, like many others of its time, essentially came as a kit, its pieces supplied by the King Bridge Co., a firm founded in Cleveland that also had a large plant in Topeka, Kan. Staffed with its own engineers, the company fabricated thousands of bridges for sites across the country before it went out of business in the early 1900s.

The 10th Avenue Bridge consisted of a series of deep box trusses supporting the roadway above. I have to believe that quite a few adventurous souls, perhaps acting on a dare, clambered their way across the trusses, which were ready-made for youthful hijinks.

The roadway, made of wooden planks, was a mere 17 feet wide, extremely narrow by today's standards. This narrow profile may have contributed to a sense that the bridge wasn't structurally sound, according to an article published in 1882 in what was then the St. Paul and Minneapolis Pioneer Press.

The article stated, rather cryptically, that the bridge "was never what it was purported to be," then went on to claim that "its present apparently insecure condition has awakened the apprehension of nearly every person who crosses it."

The words "insecure condition" cannot have inspired much confidence, nor did those of a city engineer who told the newspaper that the bridge was "theoretically safe, but there was poor workmanship … and a defective beam here or there or a badly placed one somewhere else may undo the entire theory of its strength and make it an unsafe structure."

Not exactly comforting words from an engineer, who seemed to be saying that the bridge was safe as designed but that any hidden defects could easily lead to a catastrophic failure. However poor its workmanship, the bridge held up for many years under heavy use, with as many as 1,500 horse-drawn wagons, many loaded with lumber, crossing every day along with countless pedestrians.

The bridge remained a busy crossing well into the 1880s, but newer bridges nearby gradually began to lessen its load. The first Washington Avenue Bridge opened in 1886 and a new span opened five years later at Hennepin Avenue. More bridges opened in the 1900s, including the 3rd Avenue Bridge (1918) and the current 10th Avenue Bridge (1929).

These new spans left the old 10th Avenue Bridge to languish as something of an antique, while concerns about its safety mounted. The bridge's weight limit was gradually reduced until 1934, when it was closed to all but pedestrian traffic.

World War II finally brought the bridge down.

To help with the war effort, the city donated the bridge to the federal government's scrap metal program in 1942. A photograph from that year shows Mayor Marvin L. Kline crouched by the bridge next to a sign announcing that its "460 tons of steel" (actually iron) would provide "enough scrap to make 4,000 aerial bombs."

The bridge was fully disassembled by 1943. I'm not sure why two of its five original piers were left standing, but they're a visible reminder of how important bridging the Mississippi has always been to the city of Minneapolis.

Larry Millett is an architecture critic and author. He can be reached at larrymillett.com.