Our urban landscapes have become increasingly sanitized and less biodiverse. A building body of research that shows that this has led to a depletion of beneficial microbes and that, in turn, is having a negative effect on our health. The lack of exposure to microbes from an early age is thought to have a number of consequences for human health, such as an increase in allergies and autoimmune diseases.

Guy Henderson visits Micropia, the world's first microbe zoo in Amsterdam, to find out more about the importance of the invisible world that is all around us, and inside us.

In London, microbial ecologist Dr. Jake Robinson is investigating the levels of microbes in the urban environment. He has developed a toolkit for examining the diversity of city spaces known as MIGI or Microbiome-Inspired Green Infrastructure, which can then be used to increase microbial ecosystems in inner city green spaces.

ecoLogicStudio, a design studio in east London, has radical ideas for integrating microbiology into the fabric of our architecture, including using microalgae photo-bioreactors and curtains to cover buildings in the bio-cities of the future.