If you’ve never checked out Boston.com’s photo feature The Big Picture before, now’s the time to do so: this week’s post on the subject of Earth Hour includes an incredible series of 17 photos — before and after lights-out — from around the world.

Among the awe-inspiring images, which go from bright to dark when you click on them, are:

• The Sydney Opera House;
• The Eiffel Tower;
• The Houses of Parliament in London;
• Los Angeles’ Nokia Plaza;
• The Las Vegas Strip;
• The Beijing Olypmics’ Water Cube;
• The main square in downtown Lima, Peru.

First established by the WWF in 2007, Earth Hour encourages people worldwide to switch off their lights for one hour in an effort to raise awareness for action on climate change. This year’s 28 March event saw record participation from 4,000 cities in 88 countries.

• Swedbank joins organisations observing Earth Hour
• Los Angeles to play it up big for Earth Hour
• 28 million Scouts set to observe Earth Hour