Patrick Blanc has been building vertical gardens for decades, but the one he designed for a 380-foot-tall building in Sydney, Australia, is the tallest ever. It stretches from the second to the 33rd floor. Blanc told the Wall Street Journal that it was tricky to build a garden that tall:

The tower, which was designed by Jean Nouvel, is over 160 meters high, so it has been very challenging. Altogether there are 450 different types of plants, of which 250 are local species. When a building is that high there can be a lot of strong wind so I installed a metal grill with large meshing in front of it to make sure the plants are secure.

It’s not exactly natural to grow these particular plants in these particular conditions, even when they’re local to the area. Blanc’s design uses synthetic moss as a substrate and motorized mirrors that send the sunlight to the plants. But overall, the garden’s supposed to contribute to cutting the building’s energy use, and there’s something really compelling about the idea of looking out a 20-somethingth story window and seeing a hanging garden.