Thirty-one apartment buildings comprising 140,000 m 2 of floor space: Europe’s most ambitious energy-saving renovation project is transforming Torrelago, a residential district of Valladolid in central Spain.

As the number of smart cities increases, the heavier are their responsibilities towards citizens.

  In the suburbs of Valladolid, a city in central Spain, a district is at the forefront of Europe's energy transition.

Identifying healthy from diseased tissue poses a unique problem for cancer surgeons. Even the smallest bits of a tumour left behind during surgery can regrow and spread to other organs, a deadly phenomenon called metastasising.

Low-carbon mobility is essential to reduce greenhouse gas emissions. In Valladolid, Spain, hybrid buses use electricity in the city centre and are connected to a smart city platform which monitors how often they charge and how much.

Greenhouse gases decreased by 23% between 1990 and 2016, said the third report on the state of the “Energy Union”, which tracks the EU's transition to a low-carbon society.

Biomimicry , also called bionics, uses structures found in nature to solve everyday problems. A well-known example is the Velcro strip , which a Swiss engineer, Georges de Mestral copied from the burdocks that stuck to his dog and clothes on a walk through the fields.

Spain is known as a land of sun and heat. But even here there are regions that have to face icy winter temperatures. In Valladolid , in the north of the country, many of the almost 300,000 inhabitants are in poorly isolated buildings built in the 1960s.

Offshore wind farms play an increasingly important role in renewable power generation. According to WindEurope, Europe now has a total installed offshore wind capacity of 15,780 MW.

From 21 to 25  May the EU Green Week is exploring ways to accelerate sustainable urban transformation.

Could a human behaviour simulator be embedded into a robot or online avatar to the point that it’s hard to distinguish between a real person or artificial intelligence? Scientists have been upping the stakes in this “ Turing test ” for years, to the point that human-mimicking programmes are ready to answer tricky questions, assist people with online shopping or be companions.

Local governments in Europe are notoriously risk averse, city council officials and industry leaders won’t hesitate to tell you.

Bristol is at the forefront of high-tech innovation in the UK, named European green capital in 2015. But it is also the second least affordable major British city housing-wise only after London.

When temperatures are low, the temptation to take long, scalding showers and turn electric heaters to the maximum is high. And not knowing how much energy we spend, when we unthinkingly do these activities, makes it difficult for us to decrease our consumption.

Home sweet home. Houses are supposed to be our nest, a shelter from the world outside. But how healthy are European homes? Nowadays most of our time is spent indoors, often at home, one reason being the current shift to “desk jobs”.

“Are we all on the same page? Singing from the same hymn sheet?” For anyone working with groups of people in policy areas, the answer is nearly always “yes”.

As air pollution is largely considered to be an outdoor problem, people are little aware of indoor contaminants . The World Health Organisation estimated that each year 4.3 million people die of exposure to household pollutants.

Both European and Asian experts are focusing on the challenging tasks of system integration and transmission of renewable energy over long distances. High Voltage Direct Current (HVDC) grid technologies could be the solution.

Households and small businesses using independent power systems, or microgrids, still find it hard to cope without their national electricity grids.

When Justin Bieber made his way to Stockholm in September 2016, city officials hardly expected the tween heartthrob to pave the way for sustainable urban policy .