This artist just spray painted a public square in Switzerland

Thousands of artists are being featured at hundreds of galleries as Art Basel opens its doors in the Swiss city this week.

But before visitors even enter the art fair, they will cross a large public square sprayed with white and magenta paint — an artwork by Katharina Grosse.

The German artist is known for using spray paint to transform spaces, from an abandoned property in post-Hurricane Katrina New Orleans to a condemned structure in the Rockaways, New York. Her massive, in-situ paintings have been commissioned by contemporary art museums like MoMA PS1 in New York and the Centre Pompidou-Metz in Paris.

Grosse’s work covers the Messeplatz, a public square outside Art Basel.

In Basel, her work covers the Messeplatz, and the structures — from a fountain to benches and bins — it contains. “Even the clock will get painted a little bit,” she told CNN in early June, before she started painting, referring to the huge timepiece on the facade of one of the exhibition halls.

That required some logistical preparation, like emptying the fountain and covering it with an anti-graffiti coating so the paint can be washed away later, explained Natalia Grabowska, of the Serpentine Gallery in London, who curated the work.

The square measures several thousand square meters, or about the size of a soccer field, said Grabowska. She added that Grosse is someone who can “work at scale and really transform spaces.”

The paint covers structures like a fountain and a large clock on the facade of one of the exhibition halls.

Grosse says that the sheer size of the work, her largest to date in an outdoor setting, was a challenge for her. “For me, it’s an amazing possibility to develop my work further and test my thinking and painting,” she said.

Although the artist created models of the work beforehand, she said that things always change on site as she responds to the situation on the ground. “I have a lot of different surfaces. I have distances to bridge. I have to make it work and be vivid but coherent,” she said.

The fact that her “whole painting has to be invented on site” means that it might be “the youngest work at the fair,” Grosse added.

Grosse painted the bottom of the square’s fountain, which was drained and covered with an anti-graffiti coating before it was painted.

That made it particularly interesting to watch her paint, said Grabowska. “She works very intuitively with her body and sees where it takes her,” she said. “She walks back and forth — it is a bit like unscripted choreography, a bit of a dance.”

Grosse’s work might also be the shortest lived at the fair. After seven days, the paint will be peeled and pressure-washed away. “I think it’s the shortest lifespan of a piece I’ve done outdoors,” said Grosse. “There’s a beauty that it appears for a minute, and it’s only in your memories and the pictures we’ve taken and the way we talk about it.”

Still, she hopes that for a few days, it can help transport visitors. “It’s almost like a poetic space that’s slipped under your familiar existence,” she said.

Grosse told CNN that she hopes the work makes visitors reconsiders what a painting can be. It “doesn’t have to be like a pancake on a wall,” she says.

“Her work is so powerful that you get immersed in it instantly,” said Grabowska. “You can’t ignore it.”

Grosse also hopes that her work will help people reconsider what forms painting can take, as they enter one of the world’s most important art fairs. It “doesn’t have to be like a pancake on a wall,” she said.