Scattered throughout London's Cheapside financial district, the seats are the winning designs of the City Benches competition held by the London Festival of Architecture (LFA).
"The benches demonstrate not only the brilliance of London's emerging architects, designers and artists, but also how small interventions can make such a difference to how people can experience and enjoy London's streets and spaces," said Tamsie Thomson, director of the LFA.
"Cheapside is one of London's liveliest and most interesting districts, and thanks to the support of the Cheapside Business Alliance, is a setting where these young teams can showcase their work to hundreds of thousands of people."
The five winning benches were created in response to the theme of this year's festival, boundaries, and are intended to highlight the need for well-designed spaces for pedestrians in cities.
One of the designs is Benchtime by architect Anna Janiak, which is modelled on the The Jantar Mantar monument in New Delhi – a collection of life-sized astronomical instruments that double as a playground.
Installed at 150 Cheapside, it is designed to stand out from the surrounding stone architecture, and acts as a sundial to indicate time throughout the day.
Astrain Studio Architects created a series of geometric benches inspired by children's play blocks, in a bid to bring a feeling of youth and playfulness to Cheapside.
Named City Blocks, they are nestled within Cheapside Sunken Garden, and wrapped in a mix of colourful tiles intended to introduce a domestic, human scale to its outdoor setting.
Over in Bow Churchyard, Delve Architects with DragonSmoke Construction installed a giant, sleeping dog, named Whippet Good.
Designed in response to research that demonstrates the positive impact of dogs in the workplace, it is designed to "counteract current political and economic turmoil".
Whippet Good sits along Love Without Borders bench designed by Armor Gutiérrez Rivas and Atelier La Juntana, which responds to the number hard borders dividing countries throughout the world.
It has a gridded form, but is punctured by giant heart-shape void, designed to "transform the notion of a barrier into a window for social interaction".
Correlated Journeys by artist Sarah Emily Porter and maker James Trundle is the last of the five City Benches, positioned in front of the Royal Exchange.
It has a rectangular form with curved edges, and is adorned with a stripy multicoloured finish, which represents London's complex underground transport network.
The benches will remain in place for the duration until the end of August.
Elsewhere in the city, designer Yinka Ilori has teamed up with architecture studio Pricegore to create a multicoloured pavilion outside Dulwich Picture Gallery, and leading UK architects have installed architectural paper-models at the V&A.