As an architecture student, Leila Araghian, 31, recalls roaming the sycamore-lined boulevards of her hometown, Tehran, looking for the next adventure. Once, she and a friend were passing by a bridge along Zafar Street, when they spotted a brown leather sofa outside a building.

So they got an idea, and dragged the sofa onto a small bridge, one of many that dot the creeks running through Tehran. As they sat there watching the water flow beneath them, they thought how much better it would be, if people could actually hang out on bridges, rather than just cross over them.

That friend, Alireza Behzadi, would become Araghian's collaborator in her most important project so far, the Pol-e-Tabiat, or Nature Bridge, which opened in late 2014, and is now being called "the third symbol of Tehran". The pedestrian bridge has won three awards in Iran.

And on Tuesday, it picked its first international recognition, winning a 2015 A Popular Choice prize in highways and bridges category, from a New York-based architectural organisation, Architizer. A panel of international jurors also nominated it as one of the top five finalists in architecture and engineering category.

Araghian recalled that late afternoon stroll with Behzadi many years ago, as she explained the inspiration behind her project, which she designed when she was only 26.

"Usually, bridges are designed in a straight line. And that straight line will produce a one point perspective that will tell you to just go. But we want to keep people on the bridge," she told Al Jazeera.

"The bridge is not just a structure to connect from one point to another, but also a place to stay and enjoy."

Soaring 270m across Modarres Highway, Pol-e-Tabiat, which connects two parks in the northern district of Iran's capital, reflects her aspirations about Iranian architecture, Araghian said.

Mohammad Mohammadzadeh, an architect, author and critic, told Al Jazeera that projects like Araghian's "reveal a huge capacity in the emerging generation of architects, who have been willing to form a progressive trend in Iran".

To achieve her goal, Araghian designed Pol-e-Tabiat to have three layers, including one level for cafes, another for walking, running and biking, and a third platform for viewing the highway below, or the Alborz mountains, which towers beyond the skyline of Tehran.

Entering from the west on Ab-o-Atash (Water and Fire) Park, the bridge opens with a 60m-wide entrance with flower gardens, making it appear like it is still part of the park. The multiple paths, sourced from "100 percent recyclable composite wood", lead visitors to the different levels of the bridge.

Supported by three tree-like columns, Pol-e-Tabiat was built with a curved body, to give visitors different perspectives depending on what they are facing, Araghian said, explaining the merits of Iran's largest pedestrian bridge.

"So when you are walking on it, you don't really see where you are heading, adding to the mystery, as if you are walking on a path."

To put up the bridge's foundation, Araghian and her team also searched for a spot where there were a minimum number of trees.

It took a year for Araghian and her team at Diba Tensile Architecture to design Pol-e-Tabiat. They worked with the Italian engineering firm Massimo Maffies for the construction, which started in the fall of 2010.

Behzadi, who oversaw the construction, said installing the 2,000 tonnes of steel hundreds of metres high above a major highway, was the most challenging part of their tasks. Engineers had to set up a platform to ensure the safety of workers. Temporary tunnels were also built to prevent construction materials and other objects from hitting the cars buzzing below.

Because of the trade sanctions imposed on Tehran, obtaining construction materials from overseas was also a headache. Contractors had difficulty transporting materials and paying for them, which caused delay on the project.

Four years, 10,000 cubic metres of concrete, and millions of labour hours later, the bridge was completed last October.

Walking around the bridge following the inauguration, and seeing for the first time the stream of people enjoying her work, Araghian said, "It felt good of course."

"All the things I had in my mind, where the people would go and where they would sit, they all functioned the way I imagined it. That really felt good because it's my first project."

Araghian, who was studying in Canada during the construction, said that Behzadi should share equal credit in the project, for pushing her to enter the bridge design competition, and for looking after the project through to the end.

"He was the reason why I did the work and he was the one who stood [by my side] in the worst situation," she said. "There's no bridge without him."

Later, as Araghian and Behzadi observed visitors' reactions to their project, they realised how Pol-e-Tabiat bears some resemblance to the stone bridges of ancient Persia. Until now, hundreds, if not thousands of people still hang out in the arches, passages and corners of the 400-plus-year-old Khaju Bridge and Siosepol, or the Bridge of 33 Arches, which traverse Zayandeh River in Esfahan, one of the capitals of the ancient Persian Empire.

Arash Mozafari, an architect who works in Canada and Iran, said Tehran needs more public spaces like Pol-e-Tabiat.

"I believe this project has a really wonderful design," he said. "It is not just a bridge. It is a popular public space, an urban space for pedestrians."

He said that while Pol-e-Tabiat is being mentioned alongside Azadi and Milad Towers as symbols of Tehran, "these are not comparable" because the towers represent something more political, whereas Pol-e-Tabiat "is for the people and nature".

He also praised Araghian as a "talented young architect."

"We will hear more from her. She knows the methods of design and engineering very well, and she is a very hard worker, qualities one can hardly find these days."