From a huge canvas to a sweeping concrete wall, paintings are a relatively simple and straightforward large-scale art project. Bring several artists together and work on individual sections, or block out several days to do it yourself. Paintings can be done with any type of paint, although any outdoor murals should be composed with durable, environmentally friendly materials. For inspiration, look at modern large-scale paintings like the murals sponsored by the Philadelphia Mural Arts program or the two-mile long picture in Vadodara, India, made by students to commemorate Ghandi's birthday.
Sculptures can be made out of almost any material: metal, glass, rock, plastic, Legos, thumbtacks and even recycled objects. Joshua Allen Harris, a New York City street artist, makes trash bags come to life over subway vents, and Tim Noble and Sue Webster, a contemporary British art team, create detailed shadow scenes using piles of rubbish. Sculptures can be mildly ironic, like a giant coffee cup made out of coffee cups. They can also be visually arresting, like a huge pile of chairs and furniture hanging from windows, or they can be poignant and globally unifying, like framed samples of dirt compiled from all over the world or a collective depiction of a religious figure.
Photography does not have to be restricted to 3-by-4-inch photo paper. Print a photo on a larger piece of paper, or hang several photographs around a room to tell a visual story. Collect photographs from all over the world of a single type of object. Hang rows of photographs of single colors to create an image. Denise Marika, a New England artist with a focus on context, once projected a series of 8-foot photographs on a wall in Boston, and the "New York Times" sponsored a world-wide project to capture the world in photographs at a single moment, asking professionals and amateurs alike to snap a picture at precisely the same time around the globe.
The Internet has made collaborative and large scale non-visual art much less challenging. Collect music from around the world and weave it into a song, or collect thousands of renditions of a single piece. Employees at Google established the YouTube Symphony Orchestra by asking musicians around the world to play a certain piece of music. They then wove these pieces together to create a single performance. Another growing global trend is the flashmob, which is essentially a sudden, seemingly random, pre-planned performance piece in a public space. The London Underground was filled with silent disco dancers in 2006, and dance tributes following the death of Michael Jackson occurred around the world in 2009. Bring together a large group of people to perform an impromptu scene from Shakespeare, or organize a city-wide scavenger hunt.