With increasing global population and the growing sizes of horizontal cities which require much areal expansion on land that otherwise can be used for parks and green areas, vertical cities may very well be an alternative for housing. Though horizontal cities have many advantages, brought comfort to their citizens, contributed in organization of daily life and facilitated employment and effectively coupled businesses to the socio-economic conditions in societies, Yet, the fast urbanization and the huge expansion of horizontal cities come with several forms of negative impacts such urban-heat waves, increasing pollution and waste, land degradation and associated effects on water, energy, natural resources, biodiversity and life-quality. These environmental changes along with climate change will still trigger further wicked and multi-layered threats.

Vertical cities can be can be constructed in different 3D-architectural structures with interlinked flours that have environment and self-sustainable towers extending high in the sky. These 3D architectural buildings can save energy, water and preserve horizontal land for forest, agriculture and food production as well as promotion of recreation and biodiversity. These are of importance for supporting the UN-SDGs and promoting life-quality and prosperity. With modern technology and AI ‘Artificial Intelligence’ maintenance and running costs of vertical cities can be more economic and effective than traditional horizontal ones (https://youtu.be/d0gqonPNBgU).

There are growing sources of information and data on vertical cities, the involved technologies and other issues of relevance. The vertical city organization (https://verticalcity.org/index.html), for example, has the mission to inspire the ongoing conversation for the creation of new systems of living and was established by Ken King in 2012, Its aim is to ignite global debates about vertical cities as a more sustainable future with large and urgent solutions to the existing problems. It has team members in Portland Oregon, New York City, and Shanghai. It is supported by dozens of architecture, urban planning, energy, and sustainability experts that contributed with insights into the vertical city concept.

There are also books that give wide-range of the state-of-art on vertical cities. The Vertical City book ‘A Solution For Sustainable Living is a massive, is a multicolor, seminal and beautifully printed book. In this groundbreaking work, the authors Kenneth King and Kellogg Wong interviewed more than 30 of the world’s top architects, urban designers, engineers, microbiologists, transportation and sustainability experts before developing their proposal for vertical cities (https://verticalcity.org/index.html). The book itself envisions a sustainable future as based on emerging technologies of Vertical Cities. A Solution to Sustainable Living is the first and only book of its kind but this Kickstarter campaign is about way more than the book. The author Kenneth King was born in Shanghai in 1933 and currently living in New York City. He is an ecologically-driven and experienced architect with more than 40 years of professional work, known for the Montazah project in Alexandria, Egypt and Mokkattam project in Cairo that become a model for waste management in developing countries (https://www.kickstarter.com/projects/rayking/vertical-city-a-solution-for-sustainable-living).

Among other books is ‘Vertical Cities: 12 Towers Take Urban Density to the Skies’ in which it describe the advantage of the virtually endless vertical space within urban centers, entire cities-within-cities that could spring up into the skies, packing in thousands of new housing units as well as parks, recreational space, offices, shops and everything else you’d expect to find in traditional cities. These 12 residential skyscraper designs build up instead of out, often using staggered or stepped arrangements of stacked modules to maintain air circulation, access to daylight, views and other features as well (https://weburbanist.com/2015/06/17/vertical-cities-12-towers-take-urban-density-to-the-skies/). An alternative other than creating closed class-based communities, most make their communal spaces open to the public, and reserve the ground level for greenery. Examples on vertical cities (or semi-vertical cities) include: high-rise high-density tropical living in Singapore; stacked modules in Vancouver; vertical village in Singapore by OMA; vertical city in Jakarta; Burj Khalifa in Dubai.