The event, which takes place in the UK from 8.30pm, will see more than 700 landmarks around the world switch off their lights, including Christ the Redeemer in Brazil, France's Eiffel Tower and more than 30 Unesco World Heritage Sites. WORDS: PA.
The Palace of Westminster, Blackpool Tower and Edinburgh Castle are among the UK sites to take part.
London's South Bank will be the "focal point" for the Earth Hour switch off, WWF said, where visitors can experience candlelit dinners in many of its bars and restaurants.
British tennis champion Andy Murray, a WWF global ambassador, has backed the campaign along with Prime Minister David Cameron and Labour leader Ed Miliband, the charity added.
Earth Hour was launched in 2007 in Australia and has since spread around the world.
Last year nine million people in the UK took part, WWF said, as part of a record-breaking chain of 162 countries.
Exclusive tours of world-famous attractions
UK landmarks to go dark for Earth Hour
One of the most iconic holidays is touring Egypt's ancient kingdoms and while many tourists are happy to gaze at the Pyramids of Giza from afar and take in the River Nile from their resort, you can experience an exclusive insight into the wonders of Egypt. Abercrombie & Kent offers a small group tour (nine days from £2,450) taking travellers to the Pyramids of Giza in Cairo to The Twin Temples of Abu Simbel and beyond. The exclusive trip includes the option of a private viewing of the magnificent tomb of Nefertari, usually closed to the public. The final resting place of Ancient Egyptian Queen Nefertari Merytmut, in the Valley of the Queens, is a spectacular sight adorned with incredible artwork. The holiday also includes a visit to a Nubian village to discover ancient local heritage and a sailing trip aboard an authentic Egyptian felucca around the Aswan Islands.
If you've always wanted to be in the company of an astronaut, you can do more than just meet one at Orlando's Kennedy Space Center Visitor Complex. Visitors to the attraction can enjoy a delicious meal with a veteran member of NASA’s Astronaut Corps at the one-of-a-kind Lunch with an Astronaut (adults £19; children £10). You'll be able to answer questions, pose for pictures with an astronaut and hear stories of the education, dedication and courage it takes to travel into space.
A visit to the spectacular Palace of Versailles is a must if you're a fan of all things grand and royal about France. Located just 20km from the Paris, the chateau is one of the most beautiful achievements of 18th-century French art and consists of the royal apartments, ceremonial rooms and gardens built by Louis XIV. Viator's VIP tour allows you to soak up the surroundings and be treated like a royal. The full day tour (from £155 per person) offers a rare private viewing of the palace’s Royal Quarters and allows you priority entrance to Versailles through a reserved door and unprecedented access to the private rooms of Louis XV and Louis XVI, which are normally off-limits to the public, such as Louis XVI’s library. Groups are limited to a maximum of 16 and you'll have a tour of the State Apartments and the famous Hall of Mirrors before the crowd arrives.
If American drama Nashville has inspired you to hit America's South, you'll want to book a spot on Travelsphere's new Deep South tour (from £1,599 per person for 14 days), which follows the route of music legends Johnny Cash, BB King and Elvis Presley, and features a private performance in Nashville by John Carter Cash, Johnny Cash’s son, or Tommy Cash, his brother. Travelsphere guests will be the only people at the special, intimate gig. Other highlights of the tour include Memphis, where you can visit the location for Elvis Presley first recordings Sun Studios, famous country music venue Grand Ole Opry and the home of jazz New Orleans.
The Vatican's Sistine Chapel is notoriously swarmed with tourists who come to see the magnificent chapel and official residence of the Pope. So much so that the millions of visitors will soon have to pass through a vacuum system to prevent the the dust from their clothes from damaging the renowned frescoes. But you can get VIP treatment when you tour the Vatican and Sistine Chapel with Viator, from £205 per person in a group no larger than 10. You'll have a private view of Michelangelo’s ceiling before the other tourists step in, follow an expert guide and under the escort of a key-holding Vatican official to enjoy 30 minutes alone to enjoy the Sistine Chapel, as well as have access to rooms normally closed to the public, such as the Niccoline Chapel and stunning Bramante spiral staircase.
Africa is home to stunning landscapes and beautiful wildlife, and what better way to see it than from the sky. Abercrombie & Kent offers the ultimate African safari where you will be transported in the lap of luxury in a private jet. The 19-day journey, priced from £55,000 per person based on two sharing, includes the most exclusive highlights of the continent with the jet landing in places large commercial planes can't, taking you right to the heart of the action. Explore the ancient churches of Ethiopia, search for gorillas in Uganda and marvel at Victoria Falls from a helicopter. Theres is also a three-day safari in Tanzania's Serengeti with founder of Abercrombie & Kent, Geoffrey Kent.
Ever wanted to see inside the Houses of Parliament? As a UK resident you can take a free tour by writing to your local MP or a Member of the House of Lords. The tour takes in one thousand years of history, stunning art and architecture and modern day politics. You'll be shown around Westminster Hall, the Commons Chamber and the Royal Gallery. You can also climb the Elizabeth Tower (Big Ben) on a tour that will take you 334 stone spiral steps to the top of the 153-year-old tower. As these tours are high in demand, early booking is recommended.
Monastery-turned-hotel Monastero Santa Rosa on Italy's Amalfi Coast is giving guests a fascinating glimpse at the past with private excursions to Pompeii and its 'little sister' Herculaneum. The cities were buried by a volcanic eruption of Mount Vesuvius in just 24 hours in AD 79. While Pompeii is one of Italy's most famous attractions, the lesser-known Herculaneum attracts far fewer tourists and is often overlooked. Monastero Santa Rosa offers a half-day private excursion to Pompeii or Herculaneum (£212 for up to three people) or a full-day excursion to both (£339 for up to three people), taking in the famous archaeological sites with a guide on hand to provide information and tips and the luxury of bypassing the often long ticket queues.
Cruisers visiting St Petersburg with Silversea this summer can experience a unique visit to the Hermitage Museum. As well as having early access to the museum before it is open to the general public, the tour will be guided by the most experienced and knowledgeable Hermitage curator, taking you through the Ancient Greece, Ancient Italy and Ancient Roman collections of the Hermitage Antiquity Department. Silversea's Silver Whisper 4315 voyage sets sail on 5 July 2013 for seven days from Copenhagen to Stockholm and costs from £2,250.
As the largest religious monument in the world and Cambodia's prime attraction, Angkor Wat is a truly special place to visit but it can get very crowded. With Travel Indochina you can get insider access to Angkor Wat, entering via the lesser-used eastern gate for a more intimate experience away from the crowds. The special sunrise visit means you also have to pass through the jungle illuminated only by torchlight before viewing the wonderful temples at dawn. The seven-day Highlights of Cambodia holiday costs from £785 per person, including the exclusive tour of Angkor Wat.