March 24, 2013 — Millions of people around the world marked the arrival of 8:30 p.m. on Saturday by turning their lights off for Earth Hour.
Across the globe cities went dark for one hour on Saturday to celebrate Earth Hour.
7,000 cities participated in the event from 152 countries.
Lights deemed not essential to public safety were turned off for the annual event.
The event was led by the World Wildlife Fund, which hoped to raise global awareness about climate change that extends beyond the hour-long event.
The island of Samoa in the south Pacific was the first nation to participate Saturday, 13 hours ahead of Greenwich Meridian Time (GMT).
There were many nations participating for the first time this year, including Palestine, Tunisia, Suriname, French Guyana, and Rwanda.
Around the world many famous landmarks went dark.
The Pacific region was the first to celebrate Earth Hour, with Fiji hosting the world's first ever Earth Hour Night Bike Ride in the capital Suva.
Sydney's famous Harbour Bridge and Auckland's Sky Tower went dark on the hour.
In Asia, some mega towers including Seoul's Namsan tower, Taipei's 101 building, and Malaysia's Petronas twin towers were noticeably less imposing Saturday night.
This year's Earth Hour was a time of reflection for many Africans as countries across the continent try to balance growth with environmental sustainability.
Egypt's great Pyramids went dark while this year's Earth Hour was Libya's first environmental movement post-Qaddafi.
The Middle East also shut its lights.
The Burj Khalifa in Dubai was a noticeable participant while in Palestine, Gaza and the cities of Nablus, Bethlehem and Ramallah all held events.
Europe's most famous landmarks including Buckingham Palace and the Eiffel Tower shut their lights while for the first time the Kremlin announced its participation in the campaign to promote saving energy.
Other noticeable landmarks participated including the Acropolis, Holland's Erasmusbrug Bridge, and the Brandenburger Gate.
Canadian's were enthusiastic participants of Earth Hour, electricity providers in Nova Scotia and Ontario reported drops in demand.
Niagara Falls receded into the darkness for thousands of people in attendance.
Vancouver was given the honour of being declared "capital" of Earth Hour 2013.
The city's effort to become the "greenest" in the world was recognized by a panel of judges deciding between six finalists.
In the United States, big changes were noticed when Times Square and the Las Vegas strip turned off their lights.
South America got in on the celebrations with one of the new 7 Wonders of the World - Iquitos, the city where the Amazon River begins, taking part.
Festivities also occurred in Rio, Buenos Aires, and the Amazon.
The tiny Cook Islands were the final participants to welcome Earth Hour, almost 24 hours after it first started.