Northern Spark might have left Minneapolis for St. Paul, but that doesn’t mean the late-night celebrating is over. The Mill City has come up with its own downtown nighttime festival, Secret City, which is joining forces with Greenway Glow, the bicycle and art fest that was part of last year’s Northern Spark.

The festival, which will begin at 6 p.m. Saturday and end at midnight, will involve multiple locations, including the Convention Center, the downtown stretch of Hennepin Avenue and the Midtown Greenway bike path in south Minneapolis. It also includes some places typically not associated with the arts.

Ready for an art party under a freeway overpass? The parking lot between the Walker Art Center and the Basilica of St. Mary will be home to an art installation and live performers.

“One of the taglines is ‘hidden in sight,’ ” said Mayor R.T. Rybak. “The idea is to go into familiar areas and illuminate them in a new light.”

Special pedestrian and bike lanes will be in place to encourage participants to walk or bike between locations. The festival will include an array of offerings, ranging from music, dance and art to public ping-pong tables.

All the events are free with the exception of an annual fund­raising ride that is part of the Greenway Glow. (You can participate in the other Greenway events without taking part in the fundraiser.) Food trucks will have refreshments for sale, and there will be a beer garden adjacent to the Greenway.

Secret City and Greenway Glow started as separate festivals. Last year’s biking event drew 2,000 people to the Green­way, and when Northern Spark (which was held June 8) announced that it was moving to St. Paul, the coalition started working on ways to continue the art fair, said Soren Jensen, executive director of the Midtown Greenway Coalition.

“When we heard that the city also was planning a festival, we decided to join with them,” he said. “We’re thrilled to be part of Secret City.”

The festival’s centerpiece is MIMMI (Minneapolis Interactive Macro-Mood Installation), a cloudlike sculpture in the Convention Center Plaza. The sculpture changes color after sunset depending on the collective mood of the city’s residents, which is determined by the tenor of their social media comments.

“The Minneapolis Convention Center feels that the center plaza area is underused as a gathering space,” said Gülgün Kayim, the city’s director of Arts, Culture and Creative Economy. “The idea was to put art there to engage people and make them aware of the plaza.”

Meanwhile, the Hennepin Cultural District, which was created by the City Council in February, was looking into ways to re-energize the stretch of Hennepin Avenue between the Walker and the Mississippi River. What Kayim calls “pop-up art” — temporary art and performance displays — seemed like a perfect fit.

“The Hennepin Theatre Trust also is getting involved,” she said. There will be free performances at the Brave New Workshop and salsa dance lessons at the Cowles Center. “We’ve even got Block E open for rehearsals of Fringe Festival shows,” she added.

The Greenway Glow will be much like last year — only much bigger, Jensen said.

“We’ve got a 5 ½-mile-long art gallery,” he said. “Last year, we had 17 artists. This year, we’ll have more than 40.”

He isn’t sure of the exact number because although registration is officially closed, he’s having trouble turning down latecomers.

“Someone calls up and says, ‘We’re a group of violinists’ and I say, ‘That sounds cool. We’ll find you a space.’ ”