Photo by Abby Gillardi.

You never know what you'll find at St. Louis Swap Meet.

Grab your crafts, instruments and food trucks — or maybe just your wallet. Cherokee Street's wildly popular swap meet is expanding to the Arch, and you're invited to join in on the fun.Starting in July, the brand-new Riverfront Marketplace will offer a two-day shopping and dining experience (with a biergarten!) on the Arch grounds on the third weekend of each month through October. A partnership between the St. Louis Swap Meet and Great Rivers Greenway, the new flea market hopes to bring new life to the Arch grounds.Martin Casas, who launched the St. Louis Swap Meet on Cherokee Street last spring, has high hopes for this new offshoot."With thousands of visitors each weekend, the Arch Riverfront is the perfect place for a Swap Meet," Casas said in a press release. "This is the first place everyone imagines when they think of St. Louis, even Missouri, so we want to use it to showcase the best of what our small business owners in the region have to offer. We want people to spend more time down here, and we think this is the perfect solution."When Casas founded his flea market on Cherokee, he was initially met with some opposition — chiefly from neighboring antique stores who feared increased competition. He's almost certainly getting no such static from stakeholders near the Arch, as there simply aren't many businesses nearby to object. Visitors walking to the Arch grounds are often left wondering "what next?" — a question Casas hopes to answer with stalls offering vintage clothes, crafts, antiques and small-batch food items.Matt Brinkman, special events director for Great Rivers Greenway, expressed his excitement about the project."We are thrilled to be welcoming the Riverfront Marketplace to our lineup of new events as part of our opening summer on the riverfront," Brinkman said in a statement. "I hope area residents will take this opportunity to see our new riverfront in action and catch up on the progress of construction on the Arch grounds."Artists, cultural organizations, crafters, food and drink vendors, boutique owners and musicians can apply for a spot at the Riverfront Marketplace on the St. Louis Swap Meet website by the first of each month. There are opportunities for branding and sponsorship as well.The first Riverfront Marketplace will be July 16 and 17 from 10 a.m. to 3 p.m., while the St. Louis Swap Meet continues on Cherokee on the first and last Sunday of the month.And if you're planning a visit to the Arch, check out the new-and-improved northern grounds here