On March 19, dozens of countries around the world observed the 10th annual "Earth Hour."
Famous landmarks around the world — and millions of private citizens — turned off their lights for 60 minutes at night to create stunning, rarely seen images of their cities.
1. Here's the Parthenon in Athens, Greece, with its lights on...
The Parthenon, lights on. Photo by Panagiotis Tzamaros/Getty Images.
2. ...and off.
The Parthenon, lights off. Photo by Panagiotis Tzamaros/Getty Images.
3. The Petronas Towers in Kuala Lumpur, Malaysia, look plenty majestic all lit up.
Kuala Lumpur's Petronas Towers, lights on. Photo by Mohd Rafsan/Getty Images.
4. And young-adult-novel-dystopia eerie in the dark.
Kuala Lumpur's Petronas Towers, lights off. Photo by Mohd Rafsan/Getty Images.
5. The lights on Big Ben and Britain's Houses of Parliament were also switched off for Earth Hour.
London's Big Ben and Parliament buildings, lights on. Photo by Niklas Halle'n/Getty Images.
6. Which made the complex look not unlike it had been overrun by dark wizards.
London's Big Ben and Parliament buildings, lights off. Photo by Niklas Halle'n/Getty Images.
7. Earth Hour started in 2007 in Sydney, Australia...
The Sydney Opera House, lights on. Photo by William West/Getty Images.
8. ...in order to bring attention to the threat of global climate change...
The Sydney Opera House, lights off. Photo by William West/Getty Images.
9. ...and convince the world to heed the warnings about imminent global catastrophe from scientists, activists, and religious groups — notably the Vatican.
The Vatican's St. Peter's Basilica, lights on. Photo by Vincenzo Pinto/Getty Images.
10. Pope Francis has said, of climate change, "Any harm done to the environment ... is harm done to humanity.”
The Vatican's St. Peter's Basilica, lights off. Photo by Vincenzo Pinto/Getty Images.
11. In the nine years since the first Earth Hour, the event has expanded to include iconic landmarks around the world, like this — the famous "Chain Bridge" in Budapest, Hungary.
Budapest's Chain Bridge, lights on. Photo by Attila Kisbenedek/Getty Images.
12. Though it's been frustratingly slow at times, some actual, real-life headway on climate change has been made since then.
Budapest's Chain Bridge, lights off. Photo by Attila Kisbenedek/Getty Images.
13. Especially in Paris, where a historic climate pact was signed in December.
Paris' Eiffel Tower, lights on. Photo by Ludovic Marin/Getty Images.
14. 195 countries reached the landmark agreement together...
Paris' Eiffel Tower, lights off. Photo by Ludovic Marin/Getty Images.
15. ...including top polluters the United States and China. Shanghai (pictured below) was a 2016 Earth Hour participant.
Shanghai, China, lights on. Photo by Johannes Eisele/Getty Images.
16. The agreement commits the nations that signed to take immediate action in order to limit total global temperature rise to 2 degrees Celsius.
Shanghai, China, lights off. Photo by Johannes Eisele/Getty Images.
17. Critics of Earth Hour have knocked the annual event for being more symbol than substance. After all, what does it matter if the Wat Arun in Bangkok, (below) turns off its lights for a few minutes?
Bangkok's Wat Arun, lights on. Photo by Christophe Archambault/Getty Images.
18. After the lights go back on, polluters will still pollute, politicians will still stall and delay, and nothing will change. At least not right away.
Bangkok's Wat Arun, lights off. Photo by Christophe Archambault/Getty Images.
19. But when young people gathered around the Trevi Fountain in Rome...
The Trevi Fountain, Rome, lights on. Photo by Vincenzo Pinto/Getty Images.
20. ...which really shows its age in the dark...
The Trevi Fountain, Rome, lights off. Photo by Vincenzo Pinto/Getty Images.
21. ...and business people in downtown Jakarta, Indonesia, see the lights go out and...
Downtown Jakarta, lights on. Photo by Bay Ismoyo/Getty Images.
22. ...we're all thinking about are how our actions and the fate of the planet we all have no choice but to keep living on are connected...
Downtown Jakarta, lights off. Photo by Bay Ismoyo/Getty Images.
23. ...it's enough to give you hope that the world is maybe, finally, getting it. Yes, it is only a small symbolic gesture. But seeing the National Stadium in Beijing (below) go dark for an hour isn't nothing.
Beijing's National Stadium, lights on. Photo by Wang Zhao/Getty Images.
24. It's progress. And if we can coordinate something like Earth Hour at a dozen of the world’s most famous landmarks, then surely we can coordinate more meaningful change too.
Beijing's National Stadium, lights off. Photo by Wang Zhao/Getty Images.