Ghost Tree by Yixin Wei
Ghost Tree, Yixin Wei

Memorial to the
Sixth Extinction

Washington, United States, 2020

This case study concerns a hypothetical memorial to the 6th extinction located in the center of Washington DC. The challenge for graduate students at the Weitzman School of Design was to create a memorial to an event that has happened, is happening and is also yet to happen – one that doesn’t remember or edify the human subject but instead questions the human as nature’s self-appointed executioner and do so in a way that manipulates the well-known semiotics of memorials toward a new effect.

Cathedral of the Sixth Extinction

Marzia Micali

Biodiversity operates at three different scales, 'within species,' 'between species,' and in the larger one of 'ecosystem diversity,' based on symbiotic relationships that can be influenced by the disappearance of one single entity. The Cathedral of the Sixth Extinction wants to be a commemoration of this vulnerable relationship and, at the same time, a celebration of the beauty of biodiversity. The design is characterized by 7762 poles, signifying the number of critically endangered species classified by IUCN, which create one single entity, like a cathedral window pattern. The memorial is divided into two levels, the ground one for the public, the forest of DNA codes, and the underground, with a conference center. The concept of biodiversity loss is given by exploring space and the disappearance of the poles in the underground when a species becomes extinct. Getting closer to the center, the bars lose their colors and texture, representing DNA and other physical traits of the species, becoming wholly transparent and symbolizing humans' loneliness when all the other species are gone. In response to a memorial for an ongoing event, the Cathedral of the 6th Extinction is also open to different ends. If the decline of biodiversity continues, the poles will disappear from the ground, leaving a mark, a sign of something beautiful and unique that is no longer there.

Totems of the Sixth Extinction

Yun Wang

In this proposal, the 35,765 threatened species currently on the IUCNs Red List are marked with wooden poles (totems) shipped from all across the world. The poles are treated and installed on a grid across the 160 acres of turf ground at the national mall. Each pole has a tag with a red listed species and their status; vulnerable, endangered, critically endangered etc. Each year on Earth Day, maintenance staff cut down the poles of the respective species which have become extinct. The cutting of the poles will gradually decompose the grid. When the poles form an enclosed patch, maintenance staff will clear the land and seed wildflowers. Over time, the project will turn the original monoculture turf ground into a flowering meadow, an elegy to loss.

Elegy for the Sixth Extinction

Melita Schmeckpeper

Buried under the National Mall lies the massive vault of Smithsonian Subway Station. It is embedded in 70,000 years of geologic time, in sediments deposited by floods of glacial meltwater during the last Ice Age. Over this timeframe, the site gradually shifted from tundra to open parkland to boreal and deciduous forests. European colonization and global industrialization then drove an acceleration of environmental change, accompanied by the extinction of many species. To display this transformation at a comprehensible scale, the memorial maps the 70,000-year history of the site onto one year, contrasting the sites’ rich history with the rapid environmental catastrophe of today. By projecting imagery of the site’s past onto the cave-like architecture of the subway vault, the memorial evokes visitors’ connections to environmental change in a visceral, emotional manner. Species that have inhabited the site in the past roam and flicker across the vault walls, only to be overtaken and erased by the shadows of arriving trains. By contrasting the slow rhythms of the site’s long history with the mechanized acceleration of today, the memorial emphasizes extinction as an ongoing process that underlies and haunts daily life.

Ghost Tree

Yixin Wei

The memorial for the 6th Extinction is a tomb for a giant sequoia (Sequoiadendron giganteum), located at the foot of the Washington Monument. It underscores the Washington Monument with a horizontal line that speaks the truth about what happened in the environmental history of the United States. During the time that this tree has grown, the nation has been created. The industrial revolution has unfolded, and climate change is now a consequence. The tree is from Kings Canyon National Park in California, the only natural sequoia habitat left in the world. It was dead before cutting into the 3 pieces that fit into the transportation restrictions. Transporting the tree across the United States itself in itself a big part of this project; reminiscent of the last thing this big moved by road to great fan-fare, the space shuttle.

Institute of the Sixth Extinction

Jason Latady

The sixth extinction is characterized by massive amounts of biodiversity loss, a direct result of the global destruction of natural habitat. The Institution of the Sixth Extinction memorializes this continuously disappearing habitat in the heart of Washington D.C.

This begins with a reclamation of space along the entire length of the National Mall for the threatened natural communities of the D.C. ecoregion. The horizontal plane of the Mall is tilted to mirror the sloping transect of natural communities from highland xeric forests to lowland freshwater marshes, and to create a degree of separation and protection from the existing circulation. Two embedded buildings bookend the transect on either side, acting as the headquarters for the Institute, a space for learning and discovery, and an operations hub for maintenance and research. The recreated and conserved natural communities in between become a dynamic and living part of the museum for visitors to interact with, a space for research and learning to occur, and a reminder to the loss that is occurring locally and globally.

Within this project there is also potential for other institutions surrounding the Mall to become collaborators, such as the Smithsonian Museum of Natural History, the National Gallery of Art, and the United States Botanical Garden.

The Pyramid of the Sixth Extinction

Yiru Wang

Located at the intersection of the axes that form Washington, The Pyramid of the Sixth Extinction is a proposal for a continual construction of a pyramid form made of individual (carbon neutral) concrete blocks, each symbolizing one lost species. At the rate of species extinction (currently 24 per day) the blocks are added to the pyramid.

The process of construction is carefully curated to measure, demonstrate, and remind us of the ongoing extinction. The first year of construction will be dedicated to a 600-feet-by-600-feet platform that serves as the base and stage for future work. An offset of 30 feet on each side is reserved for construction vehicle and public access, connecting to a visitor center embedded in the retaining wall beneath the Washington Monument.

Upon the base, 5714 concrete units, each symbolizing one species that has disappeared in the past 400 years, will be placed in a grid to complete the pyramid's first phase. After phase one, the construction will follow a strict daily ritual in response to the current extinction rate.

The pyramid will be completed in 2166 with 1.2 million units, weighing over 2million tons, with a total height of 344 feet. Additional blocks related to additional extinctions thereafter can be added randomly around the pyramid.

Of course, the alternative to this is to reach a point in the next 150 years when the extinction rate at the hand of humans stops. Then the pyramid will stop.

In the interim, apart from memorializing the ongoing extinction, the changing pyramid provides the public a space for future environmental protests.


This case study (design studio) was led by Richard Weller in partnership with Rebecca Popowsky. The students were Huiyou Ding, Jayson Latady, Lesia Mokrycke, Marzia Micali, Melita Schmeckpeper, Siying Xu, Song Zhang, Wanlin Zhang, Yiru Wang, Yiwen Gao, Yixin Wei, Yun Wang Zhou Wang, Florence Tzu-Rong Twu.