A row of silos on Granville Island is among the most photographed things in Vancouver. The six towers, each 70 feet tall, were once a dull gray, but now feature a colorful crew of giants. Half of them face the boats on False Creek, and the other three look inward, towards the Ocean Concrete plant.

The silos are the work of Brazilian twins Gustavo and Otavio Pandolfo, known collectively as OSGEMEOS (Portuguese for THETWINS). The duo has been graffitiing since 1987. Their work has had a profound influence on Brazilian graffiti and spans the globe, with pieces in Asia, Europe, and North and South Americas.

In 2014 the Vancouver Biennale commissioned the twins to bring their ongoing mural series “Giants” to British Columbia. OSGEMEOS chose the silos on Granville Island to add depth to the two-dimensional pieces they normally create. Ocean Concrete has a long history of community participation and happily offered a medium for what was at the time the biggest public mural of their career.

Initial estimates were set around $50,000, which included cleaning the grime from the silos and supplying 90 gallons of paint for the undercoat. The twins went through 1,400 cans of spray paint, and the final bill ended up at $180,000, some of which was crowdsourced during the project.

Giants was part of the Biennale’s Open Air Museum, which curates international art in the city’s public spaces. None of it is intended to be permanent though; after two years the pieces are taken down or painted over to make room for new projects, unless a donor intervenes. As was the case with previous Open Air artist Yue Minjun’s “A-maze-ing Laughter.” The city was so distraught over the thought of losing the 14 laughing men statues that Lululemon founder Chip Wilson and his wife Shannon bought the piece and donated it to the city.

The fate of OSGEMEOS Giants is still uncertain. They’re a beloved addition to the Vancouver skyline, but it costs about $17,000 a year to maintain them, and someone will have to step up, just as Chip and Shannon Wilson did for “A-maze-ing Laughter,” if they’re to remain.