The eco-friendly travel trend is on the rise, from uber-sustainable hotels to ethical safari experiences. But did you know that some of the world’s most famous monuments have gotten on board with the green movement, too? From the Taj Mahal to Big Ben to the Sydney Opera House, the following international landmarks have received innovative, eco-friendly updates in recent years to help them survive and thrive sustainably in this age of green travel.

Eiffel Tower

Who knew that the 129-year-old Eiffel Tower had wind turbines tucked underneath its second-story scaffolding? As part of the city of Paris’s Climate Plan, which aims to reduce energy use in the city by 2020, New York-based Urban Green Energy (UGE) designed and installed a pair of crescent-shaped, 21-foot-high wind turbines inside the tower’s second level in 2015 , which was deemed the best location for optimal wind. Painted the same brown-gray color as the surrounding metalwork, they blend in seamlessly with the monument and are almost impossible to see. Together, the turbines produce up to 10,000-kilowatt hours a year, which is enough electricity to run the tower’s first-floor shop.  

Big Ben

It’s been more than 30 years since the last significant conservation work was carried out on London’s Big Ben. However, scaffolding went up on New Year’s 2017 and chimes swung to a halt after almost 150 years of ringing on the hour while the tower undergoes a $42 million repair and upgrade. As Ben slumbers, workers will replace intricate pieces of glass on its face, repair corrosion to the cast iron roof, and fill cracks in the neo-gothic tower’s masonry; they will also replace the lights illuminating the clock dials and belfry with low-energy LEDs. More specifically, the 28 lightbulbs behind each clock face will be replaced with energy-efficient LED bulbs able to change color and tint the clock face on special occasions. So, when the three-year overhaul is complete, Ben will be both cleaner and greener.  

Sagrada Familia

Visitors to Antoni Gaudi’s modernist masterpiece Sagrada Familia might be surprised to learn that when entering the basilica’s 21,500-square-foot crypt, they’re walking on sustainable cork floors. Made in Portugal by a company called Wicanders and selected from its CorkComfort range, the nontoxic, varnished floor comes with LEED credits and certification by the Forest Stewardship Council, which means it derives from responsibly managed forests. Cork is also a thermal insulator with the potential for substantial energy savings, all of which respects Gaudi’s love of nature and affinity for using natural materials. 

Sydney Opera House

The trademark feature of the Sydney Opera House is undoubtedly its gleaming, sail-shaped roof, which rises 220 feet above sea level on Sydney Harbor. The so-called sails are composed of 1,056,006 white and cream–colored tiles made by Swedish company Höganäs, which had historically produced stoneware tiles for paper mills. In a nod to Mother Nature, the tiles are self-cleaning so any dirt and debris that gathers is washed away by rainstorms. There are no gutters on any of the roof sections. Instead, there are gaps in the concrete slabs that form the walkways around the buildings. Any rainwater simply flows off the roofs and through those gaps to a drainage system constructed beneath, which empties directly into Sydney Harbor, saving significantly on water use.

Taj Mahal

Mughal Emperor Shah Jahan designed the Taj Mahal in 1631 as the final resting place for his wife Arjumand Banu, who died while giving birth to their 14th child at the age of 38. But pollution from car exhaust fumes and acid rain from nearby Mathura Oil Refinery as well as the human impact from thousands of daily visitors have taken its toll on the legendary monument to love and is turning the white marble mausoleum yellow. To help control this, the Indian government has set up the Taj Trapezium Zone (TTZ), a 4,000 square-mile area around the monument where strict emissions standards are in place as well as an air control monitoring station inside the edifice. 

Empire State Building

In a project put in place by the Clinton Climate Initiative in 2010, the majestic 102-story Empire State Building underwent a three-year retrofit of 6,514 double-pane windows, treated with a thin UV-resistant film and pumped full of pressurized argon and krypton gasses that improve their insulation values. The $20-million project slashed the building’s energy consumption by nearly 40 percent and is expected to reduce greenhouse gas emissions by 105,000 metric tons over the next 15 years while trimming $4.4 million from annual energy costs. While you may not be able to ascertain any of this from the famous 86th floor observation deck, you can gaze out at the city skyline knowing that you’re standing atop one of the greenest buildings in Gotham. 

Pyramids at Giza

In 2016, the Egyptian Antiquities Authority (EAA) determined that groundwater in the low-lying areas at the Giza Pyramids threatened the longevity of these ancient landmarks. Action was needed to save the historic structures, so the Egyptian government partnered with the U.S. Agency for International Development Energy to install 18 energy-efficient, stainless steel turbine water pumps made by Rye Brook, New York–based company Xylem around the 4,500-year-old antiquities. The water pumps start when the water level reaches a specific point and are able to control the water table beneath the Pyramids Plateau, preventing erosion of the limestone and preserving the pyramids for future generations.

The Great Wall of China

With over 10 million yearly visitors, the Great Wall meanders its way across 5,500 miles from eastern to western China; it was built by slaves and prisoners of war, mostly during the Ming Dynasty (1368–1644). The strength and longevity of the wall, once a wartime blockade, has been credited to the ancient mortar that was used in its construction, which is a mix of organic and inorganic materials. The organic component is amylopectin, which comes from the porridge of sticky rice (yes—really!) that was added to the mortar. The Ming emperors evidently requisitioned the southern rice harvest both to feed the workers on the Wall and to make the mortar, which at the time of its construction caused widespread discontent among the Chinese people.

The Vatican

In 2010, the Vatican spent $660 million on an enormous photovoltaic installation and partnered with a Hungarian carbon offset start-up called KlimaFa, making Vatican City the world’s first carbon-neutral, solar-powered nation state. The Vatican’s solar installations include solar panels on the rooftop of Paul VI’s conference hall, which generate enough energy to power all of Vatican City’s 40,000 households and are estimated to have saved the Vatican 89.84 tons in oil. These initiatives were undertaken under Pope Benedict XVI, dubbed the “green pope,” and have been embraced by Pope Francis who, in his June, 2015 letter on the environment stated, “[Climate change] represents one of the principal challenges facing humanity in our day.”

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