A treehouse signifies a retreat high up in a tree, out of sight, out of mind, where you can look at the world passing down below. If you live in a metropolitan city, it’s hard to go back to nature. Luciano Pia, an architect in Italy has a beautiful vision for how people and nature can live together even if you live in an urban landscape. 
25 Verde, an apartment complex in Turin, Italy, is a woven 5-story mix of lush green trees and steel girders that let urban residents feel like they live in a giant urban tree house. The structure creates a transition from outdoors to indoor, holding 150 trees that absorb close to 200,000 liters of carbon dioxide in an hour. Pollution protection is brought to its residents, helping to eliminate harmful gases caused by cars and sounds from the street. The plants’ full foliage blocks unwanted rays of sun during summer while letting in warm light during winter. 25 Verde includes a variety of plants on its terraces. As the architect puts it, “the building is alive, grows and changes with the seasons. When all the green is fully blooming it gives the feeling of living in a tree house,” said Luciano. “You can dream of a house or live in a dream!”
The building holds 63 units, each benefiting from the terraces and vegetation beyond their windows and walls. Each plant has been chosen purposefully from various plants all around Turin. The rest of the house will have heating and cooling systems that come from geothermal energy, and the trees will be watered through a rainwater recycling system. Its innovative design takes us back to our childhood. The building was completed in 2012.