Spain will hold a series of celebrations to mark the annual Earth Hour, a worldwide movement aimed at raising people's awareness about the threat of climate change, organizers said Thursday.

Earth Hour, which falls on the last Saturday of March each year, has become one of the most important events in which people from all over the world can unite and show the need to protect our planet, Miguel Angel Valladares, director of Communications of the World Wide Fund for Nature's Spain office, told Xinhua.

The event will see world landmarks including the Empire State Building, the Eiffel Tower and the Kremlin switch off their lights for 60 minutes at 8:30 p.m. local time.

"Now there are 7,000 cities from 150 countries all over the world acting together with Earth Hour against climate change and for the environment," Valladares said.

In Spain, lights will be turned off on civic buildings and monuments in nearly all of the country's towns and cities, he said, adding that other public events, such as human scrabble played at the Plaza de la Oriente, will also be organized in the capital.

"Earth Hour is a worldwide campaign to unite people to protect the planet and climate change is the most important issue we have now to face," he said.

"Earth Hour is much more than switching off the lights, but to act in an environmentally friendly way every day of the year," he said.