As reported by National Geographic this month, iconic buildings are often celebrated for their architecture that has withstood the test of time, but what lies beneath those favorite, enduring facades – the cladding and infrastructure -- does not usually hold up so well. The majority of the world’s most famous structures were built long before sustainability, climate change, recycling and energy efficiency were key trends and mainstream buzz words. Enter the age of retrofit and restoration, which has (thankfully!) become the prevailing practice in preserving vintage structures worldwide. Some iconic structures that have set an example for others to follow include the Empire State Building in New York, the Eiffel Tower in Paris, the Sydney Opera House in Australia, the Reichstag in Berlin and the Transamerica Pyramid in San Francisco.