What 9 famous monuments around the world looked like while they were under construction

• Famous landmarks like the Statue of Liberty and the Sydney Opera House looked a bit different while they were being assembled.
• It took an impressive 14 years for the Sydney Opera House to be completed, and Antoni Gaudí's Sagrada Família in Barcelona remains a work in progress to this day. It began construction in 1882.
  

We know what famous landmarks look like today. But iconic structures like the Statue of Liberty and the Sydney Opera House looked a bit different while they were being assembled.

While it only took a handful of months for Argentines to erect the 221-foot Obelisco de Buenos Aires, built in 1936 to commemorate the 400th anniversary of the city's founding, other famous landmarks took a tad longer.

The Sydney Opera House — whose iconic "shells" are covered in one million tiles and were built using cranes designed for the job — took an impressive 14 years to complete, just in time for Queen Elizabeth II's visit to Australia in 1973.

Antoni Gaudí's famous Sagrada Família in Barcelona, Spain, which features 18 ornate towers, stained-glass windows, and numerous ruled surfaces, has been a work in progress since 1882.

Here are photos that show the construction of nine famous monuments in cities around the world — and the end result.

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The construction of the Eiffel Tower began in Paris in 1887, in advance of the 1889 World's Fair.

Gustave Eiffel's tower, which was actually designed by his senior engineers Maurice Koechlin and Emile Nouguier, is comprised of 18,000 pieces of wrought iron and cost the equivalent of $1.5 million to complete.

When it was built, the Eiffel Tower — which measures 1,063 feet — was the tallest building in the world.

Although it was meant to be a temporary structure (and would have been knocked down in 1909 if city officials hadn't realized its potential as a radiotelegraph station), la Tour Eiffel is now one of the most recognizable monuments in the world.

Today, the world's tallest building is the Burj Khalifa in Dubai.

Measuring in at 2,716.5 feet tall, the Burj Khalifa — which was completed in 2009 after five years of construction — is almost triple the height of the Eiffel Tower.