The bridge was part of Canadian politician William Hamilton Merritt's vision to promote trade within his country and with its neighbor the United States.

The Suspension Bridge was a border crossing between Canada and the United States, and it played significant roles in the histories of the Niagara region and the two countries.

In the time leading to the American Civil War, the Underground Railroad helped slaves in the United States escape across the Suspension Bridge to freedom in Canada.

After the war, the bridge became a symbol of inspiration to Americans, encouraging them to rebuild their country and pushing them to quickly industrialize their nation.

[1] In Canada, entrepreneur and politician William Hamilton Merritt helped establish several trade routes, especially in dredged waterways between the lake cities.

He envisioned a U.S. and Canadian rail network to connect the Atlantic coast with new territories in the West, and this led to a railway suspension bridge across the Niagara River below the falls.

[nb 1] In summer 1844 while taking a picnic on the river shores, near what was then the town of Clifton, Merritt read a letter from his sons to his wife.

[5] Merritt was driven to realize that vision, and he approached the relevant authorities, including Queen Victoria,[6] for permission to start the construction of the suspension bridge.

Powered by steam engines, vessels ferried people and carriages across the raging river at calmer points of the water.

Roebling submitted two designs, a conservative single-deck suspension bridge and a double-decked version,[17] both with meticulous calculations and drawings.

When he got wind of the project in 1845, he wrote to Charles B. Stuart, chief engineer of the Great Western Railway,[nb 4] boldly proclaiming that he could build a bridge for any likely purpose across the Niagara.

This raised his profile with the public and the engineering industry,[20] helping him to win the contract for the Niagara Falls Suspension Bridge.

Ellet's brainstorming sessions with his men raised several ideas including firing cannonballs with the line attached, towing it across the river with a steamer, and tying it to a rocket that would then be launched across the gorge.

The bridge engineer chose an idea inspired by Benjamin Franklin's experiment with a kite,[23] and similar to 15th-century inventor Leonardo da Vinci's plan to span a gap.

After resting several days at a friend's house, Walsh finally got his kite across the gorge and secured its line to a tree.

[36] Roebling's managerial strategy was to present papers filled with meticulous calculations and drawings,[30] but he also confronted his detractors and made bold exaltations about his work.

[51] The trussed sides and the upper and lower decks, which spanned 825 feet (251 m),[nb 12] formed a "hollow straight beam," reinforcing the rigidity of the bridge.

To address these concerns, Roebling added more guy-wires to secure the lower deck to the shores below,[47] ensuring that the bridge would not collapse due to strong winds.

[40] Roebling proved that despite popular opinion, properly built suspension bridges can safely support the passage of heavy railway traffic.

[47] The cables and guy-wires could support 7,300 short tons (6,600 t),[49] and travel journalist Alfred J. Pairpoint commented that it was normal to see 1,200-short-ton (1,100 t) trains pass over the bridge without danger.

When the frequency of passing trains was high, the trembling was noticeable to travelers on the lower deck and proved uncomfortable to some; writer Mark Twain noted, "You drive over to Suspension Bridge and divide your misery between the chances of smashing down two hundred feet into the river below, and the chances of having a railway-train overhead smashing down onto you.

Coupled with its vicinity to a natural wonder, the Niagara Falls, the bridge brought a lot of railroad traffic into the region once it was opened.

To avoid getting caught and sent back to their owners, enslaved people had to sneak across on foot or hide aboard trains and oxcarts when using the bridge.

[83] The achievement of building a large suspension bridge over a gorge in the face of overwhelming adversity—constant put-downs by the professional community, American and European—gave the United States a sense of pride.

The completion of the bridge that had been deemed impossible by the Western world gave Americans, who had lesser technical accomplishments than Europe at that time, a trophy for their achievements.

[84] The Suspension Bridge became the American symbol to brave the toughest of challenges and do the impossible, pushing their drive for industrialization even harder.

Charles W. Woodman specifically drew attention to the Suspension Bridge in his 1865 address to the United States Senate for approval to build a rail system to transport a ship out of the water and up around the Niagara Falls.

[61] Budget concerns forced Roebling to build the Suspension Bridge primarily with wood;[51] the cost of casting the components out of iron and transporting them "[way] out West" was exorbitant.

As the industrialization of the United States moved forward rapidly, the introduction of the Bessemer process greatly lowered the cost of the more durable steel and iron.

[65] By August 27, 1897, the last pieces of the Suspension Bridge were dismantled, leaving the Lower Steel Arch Bridge—later renamed the Whirlpool Rapids Bridge—in its stead.