The Northern Spark festival last weekend featured free public art projects throughout Minneapolis. Based on Nuit Blanche ("white night" in French), which has been taking place around the world since 1997, the local version included burning wooden artworks by seven artists at Walker Art Center for "Fire Works" and projecting data streams reflecting tweets on riverfront grain elevators for "Bumps in the Night."

Atop the Foshay, now a W hotel, the observation deck was an experience for the senses, thanks to hair-flipping winds and Caly McMorrow's "Observation Tape Deck." The installation allowed visitors to record an audio snippet and then hear it played back at various spots around the deck in unison with vintage light bulbs -- an homage to the 1929 tower's historical significance and former status as a radio transmitter.

About 1,200 people waited in line to enjoy free around-the-clock access to the 30th-floor observation deck, which usually closes at 7 p.m. and costs $8.

"[The Foshay] was my favorite spot last year," said Laura Richardson, adding that the citywide pop-up art celebration reflected well on Minneapolis. "Art is so much about creation -- when you got to these exhibits, you're part of the art, too."

Sara Glassman • 612-673-7177