In Brussels, Private Art Collections With Open Doors When you walk into the 1920s-era converted warehouse in central Brussels, you're confronted with an out-of-the-ordinary greeting: a five-meter-wide red sign stabbed through with knives whose handles spell out "Run Like Hell." If you don't heed that warning, you'll discover that the artwork by the Iranian artist Farhad Moshiri is an appropriate introduction to "Sympathy for the Devil," the second group exhibition at the Vanhaerents Art Collection, a body of contemporary art collected by the Belgian construction tycoon Walter Vanhaerents during the past 40 years. Mr. Vanhaerents oversaw every detail of the exhibition, spending more than a year selecting the art and setting up the show alongside the curator Pierre-Olivier Rolland. Sculptures, videos, paintings and photography - all chosen to reflect themes in the Rolling Stones" song that gave the exhibition its title - fill the 3,500-square-meter, or about 38,000-square-foot, space. He plans to leave the show on display for as long as three years. Mr. Vanhaerents's collection offers fans of Contemporary art a chance to see a broader, more international selection of works than they might find in a big museum or gallery; he's among a growing group of Belgian collectors who are sharing their artworks with the public, and a part of a booming art market in Belgium. "Here, there is a lack of funds for museums, and they usually show local and unidirectional art," Mr. Vanhaerents said. We open our collections for the public to have access to international collections. Mr. Vanhaerents bought the space in 2000, at a time when the Brussels neighborhood of Dansaert was still "a difficult neighborhood," he said. "It was a risk at the time, now a lot of galleries and artists" studios have moved here." In the beginning, all he was looking for was a storage space. Then, he stumbled on this "too-good-to-just-be-storage" warehouse. "It was selfish at first, I wanted a space where I could see my collection, for me and my friends," he said. But he decided that the art should be shared. After extensive renovations, the building opened as a public art space in 2007. Like Mr. Vanhaerents, Mark Vanmoerkerke has created a public venue for his private collection. It occupies two industrial buildings where he also keeps his offices in Ostend. Mr. Vanmoerkerke, a private equity and real-estate investor, said he was inspired by an earlier generation of Belgian art collectors - the entrepreneurs and businessmen who rose to prominence as Belgium's economy industrialized in the 1960s. That generation of collectors "saw art as a way to show their economic, intellectual and cultural emancipation," said Mr. Vanmoerkerke, who began his collection in 1998. In Mr. Vanmoerkerke's view, opening his collection to the public in 2008 was a natural extension of the ideal. "You want to share with others what you have assembled; it is our responsibility to share the art we have," he said. "Anyone is welcome to come and ring the bell," he said about the Vanmoerkerke Collection. Every six months Mr. Vanmoerkerke asks a different curator to put together a show from his collection of more than 1,000 pieces of contemporary art. "I give complete freedom to the curator, I love to discover new dialogues between my art pieces," he said. I learn a lot from it. "A Voyage on the North Sea," the show currently on view, is the seventh in the series. Curated by Joost Declercq and on display until September, the show is named for a Marcel Broodthaer video piece that intertwines images of a 19th-century oil painting of a ship with a 20th-century photograph of a pleasure boat against a backdrop of skyscrapers. Mr. Declercq chose the piece as an allegory of the artists" and collectors" journeys through the world of art. La Maison Particulière takes the idea of making private collections public a step further. It's a non-profit collective for collectors, housed in an airy and elegant townhouse in Brussels. The non-profit organizes shows around a theme - currently it's "Inner Journeys" through June 30 - and invites five or six collectors to show works that exemplify it. In June of this year, Anton and Annick Herbert will open an exhibition space for their large collection of Contemporary art to the public in Ghent. Last year, they sold part of their collection for more than $7 million at Christie's in New York to help finance the creation of their foundation and of the new space.