Upon first glance, Oudegracht looks like any other brick-lined street weaving through Utrecht, Netherlands. Flanked on one side by a canal and storefronts on the other, the thoroughfare bustles with pedestrians and cyclists in the early morning hours as they go about their business—but what sits underfoot is what makes this street truly unique.

Since 2012, a team of poets has been creating a never-ending poem, which is embedded into the cobblestones lining the street. Called De Letters van Utrecht, the "social sculpture" is constantly evolving and continues to expand every Saturday afternoon when one of 22 stone carvers from a local guild chisels a single letter into the stone. As the weeks, months, and years pass by, the poem evolves, continuing indefinitely so long as the city and community members support it. So far, seven poets have contributed to the project, each one writing prose until it’s time to hand the poem off to his or her successor. The poem thus far, roughly translated in English, reads:

"You have to begin somewhere to give the past its place, the present matters ever less. The further you are, the better. Continue now,

leave your footprints. Forget the flash, in which you may exist, the world is your map. If there was a time when you where another: it went by.

You are the other already. You are, as you know, the center of this story. This is eternity. It lasts. It has the time. Become one with your story and revel. Tell.

Tell us who you are with every step. In our story we vanish inevitably, only you remain in the long run. You and these letters hewn from stone. As the letters on our grave.

The cracks in the cathedral’s tower. Raised to heaven as an index finger, to identify the guilty and demand more time. So that we can walk straight again as humans along the canal.

Those staring at their feet. Look up! See Utrecht’s churches stand out. Raise your hands, beg with the towers for this privilege: to be, to be now. The weather is good.

Continue to stare. Life is witness to your gaze to the horizon. Your footsteps connect the past with written letters.…"

“Each poet is limited to 52 letters a year, since we put a new letter out every week,” Dick Sijtsma, one of the project’s founders, tells Smithsonian.com. “As long as we have poets and stone masons, [and the funding for maintenance and insurance], the poem will continue to grow.”

In order for a poet to qualify for participation, he or she must have published at least a book of poetry or two, and even if they make the cut, their proposed verses must be approved by the guild. Last year, Utrecht became the 25th Unesco City of Literature thanks to its rich literary history, so De Letters van Utrecht is able to select from a deep pool of local candidates. Ruben van Gogh, one of the founders, was the poet responsible for writing the poem’s first lines, which were then backdated to January 1, 2000 to help fill out the poem.

“Otherwise, it would have taken years for people to notice that something was going on,” van Gogh tells Smithsonian.com. “Plus, 2000 was a good year to back date it to."

So far the poem stretches the length of a single city block, but the guild of poets has mapped out its future path, which will one day wind through the city just like Utrecht's elaborate canal system. Until then, the project has grown in popularity and continues to garner attention from locals and visitors alike. Van Gogh says it’s not uncommon to see a crowd of people gather each Saturday to witness the carving and to attempt to guess the direction the verse will take.

“Once when I was visiting on a Saturday, the assigned stone carver didn’t show up, but then another stone carver just happened to ride by on his bicycle,” van Gogh recalls. “He’s the senior stone carver who trained the others, and happened to have his tools with him. He told me that he can tell which guild member did each carving based on its appearance.”

To help fund the project, people can sponsor a single stone and have the stonemason carve a special inscription on the side of it. Sponsorships often celebrate important milestones, such as birthdays, anniversaries and marriages.

“Even punctuation like colons and periods count towards a weekly carving,” van Gogh says. “People are really excited to sponsor the period at the end of a sentence.”

Sijtsma agrees adding, “One time we had someone who was coming to the end of his career, and he wanted to end that phase of his life in a symbolic way.”

So the big question: What’s up next for the poem? Sijtsma and van Gogh say that they're keeping their lips sealed.

“What the future brings is a surprise to all of us,” Sijtsma says.