Hollow is a permanent public artwork created by artist Katie Paterson and architects Zeller & Moye, located at the University of Bristol. It is a miniature forest that presents trees from around the world. Indeed, more than 10,000 unique species are represented, brought from around the world by the artists, who spent three years there. Inside the work, we can contemplate wooden blocks of all shapes, sizes and colors. The structure also includes one of the oldest trees in the world found in eastern California. This work allows visitors to admire the global environmental diversity while traveling, by the age of certain trees, throughout history.