Songdo, built on land reclaimed from the Yellow Sea in South Korea, is not even finished yet -- and is expected to cost $40 billion to develop -- but is already drawing attention for its use of technology in making city life sustainable.
A pneumatic waste system sucks residents' trash underground and straight to refuse sites, negating the need for garbage trucks; residential areas are located close to the city's business district, so commutes are a leisurely 10-15 minute walk; sensors in buildings and streets monitor temperature and can switch off street lamps when a road is deserted.
While Songdo may be on the way to becoming environmentally sustainable, is such an ambitious project economically viable? "Up-front costs are increased," Jonathan Thorpe, Senior Executive Vice President and Chief Investment Officer of Gale International, the U.S. company behind Songdo, said in a report for CNBC's Innovation Cities.
"But… operating and maintenance costs are reduced, and this translates into higher sales values, or translates into higher rents, and therefore higher property values," he added.
"So we think… [there] is a fundamental economic incentive, and economic benefit, to sustainable design."
(Read more: Latest innovations for the future's eco-cities)
In Europe, one city at the forefront of sustainability and eco-architecture is Hamburg, Germany. Voted the European Green Capital for 2011, it is used as a model example of how large, densely populated urban spaces can be turned into green, sustainable ones.
One of Hamburg's eco-friendly developments is the BIQ, the first type of housing in the world to be powered by algae.
And it's not just in housing that Hamburg is making great strides. On average, the city's residents live within three hundred meters from some form of public transport, while sixteen percent of the city is covered by forest, parks and recreational areas.
An increasing number of the city's buses are now fuelled by hydrogen, further aiding the city's ambitious plan to reduce carbon emissions by 80% by 2050.
(Read more: Secret gardens for city spaces)
"We have about 650 electric vehicles already in operation, we have fuel cell hydrogen filling stations, we have a lot of charging points here in the city." Peter Lindlahr, managing director at hySolutions, told CNBC Monday.
Despite their obvious differences – Hamburg has been around since the 9th century AD while Songdo is brand new – these two cities are prime examples of how technology, innovative architecture and ambition are breaking the traditional urban mould.
"We think that cities produce a lot of the problems with car traffic and dense housing, so we feel we need to be part of the solution," Wolfgang Schmidt, State Secretary of the City of Hamburg, told Squawk Box.