In Spain's historic port of Santander, parking is no longer a headache, rubbish bins never overflow and grass is watered only when needed since this northern resort town became a testing ground for "smart cities" around the world.

Thousands of sensors have transformed the metropolis, known for the grand hotels and high-end casinos lining its beach on Spain's northern Atlantic coast, into a high-tech laboratory.

Four hundred alone are buried beneath streets in the city's busy heart to monitor whether parking spots are free or occupied.

Light panels at intersections and GPS devices direct drivers to the nearest available parking spaces, reducing traffic congestion.

"An app allows you to pay for the parking with your smartphone and when the time runs out, you can extend it directly without having to go down to the street to put more coins in the meter," said Cristina Munoz, a 32-year-old journalist.

When Luis Munoz, an IT professor at the University of Cantabria, pitched the idea of creating a "smart city" to Santander officials back in 2009, he remembers the first thing they told him: "We have a huge problem with parking".

Seven years later, Santander, with some 175,000 residents, is a kind of living laboratory.

With funding from the European Commission and a handful of foreign universities, around 20,000 sensors are up, down and all around—under the asphalt, affixed to street lamps and riding on top of city buses.
The devices, about the size of a shoebox with four antennae, collect data on rainfall and road traffic which is sent to a control centre to help the city provide services more efficiently and cheaply.

The pilot project has made Santander the most connected city in Europe "in terms of installed infrastructure", said Munoz, and has even peaked foreign curiosity. On a recent day, the professor welcomed a delegation from Singapore that wants to share in the Spanish city's experience.

Other cities such as Boston in the United States and Aarhus in Denmark have also shown interest in working with Santander.

The city is taking part in a dozen international projects whose results are being closely monitored at a time when cities across the world, such as London and Tel Aviv, are deploying IT to deliver services.