Cattedrale Vegetale
The Cattedrale Vegetale in Italy, designed by artist Giuliano Mauri, will take decades to fully mature. (Photo: Cattedrale Vegetale/Facebook)

In a remote valley at the foot of Mount Arera, just outside the ancient town of Bergamo, Italy, stands a towering ode to Mother Nature. Called "Cattedrale Vegetale" or Tree Cathedral, this dramatic art installation is notable not only for its structural beauty but also for its unfolding timeline. Like other great cathedrals throughout human history, this particular building will take decades to complete. The only difference is that nature will effectively do all the work. Man's role is to simply step aside and let time take its course.

Cathedral Trees
A ground view of the Malga Costa cathedral's main walkway featuring some of its 80 fig tree columns. (Photo: obliot/flickr)

The Cattedrale in Bergamo consists of five naves and 42 columns, each formed by weaving more than 600 chestnut and hazel branches around 1,800 fir tree poles. A single beech tree (Fagus sylvatica) is planted within each column, capable of growing to over 160 feet tall and living more than 300 years. In the coming decades, as the man-made structures rot around them, the trees will gradually take on the structure of the five-aisle basilica.

Cattedrale Vegetale
The frame of the Cattedrale Vegetale in Bergamo was completed in 2010 as part of the United Nations’ International Year of Biodiversity. (Photo: Cattedrale Vegetale)

The Cattedrale Vegetale concept was conceived by Italian artist Giuliano Mauri, who spent years perfecting the complicated structure. He completed his first plant cathedral in 2002, composed of three naves and 80 columns, in a clearing in Malga Costa. Sadly, he passed away in 2009, less than one year before the frame of Cattedrale in Bergamo was completed as part of the United Nations' International Year of Biodiversity.

Cathedral Trees
Each of the Cattedrale's columns are formed by weaving more than 600 chestnut and hazel branches around 1,800 fir tree poles. (Photo: obliot/flickr)

When it came to the placement of the cattedrals, Mauri was very specific that they be setup within nature itself. His third installation, located in Lodi, Italy, was purposesly placed outside the city limits.

"I spoke with Mauri, but he did not consider other places," Andrea Ferrari, the city's councilor for culture, recalled in an interview. "The cathedral was to be built there, in an area where nature was not contaminated by the city and that would have left intact the evocative power of the work."

Tree Cathedral Lodi
The Tree Cathedral in Lodi is composed of 108 columns containing a single oak. (Photo: Giuliano Mauri)

The Cattedral of Lodi, completed this summer, is the largest of Mauri's designs. Occupying an area of 1,618 meters, it contains 108 columns. Instead of the beech used in Bergamo, Lodi's structure will eventually be comprised of towering oaks.