The World Trade Center was once the tallest building on the planet. Continuing our series marking the 20th anniversary of 9/11, we look at its place in the history of the world?s tallest skyscrapers.
The World Trade Center was the tallest building in the world when completed in 1971. But when it was destroyed in the 9/11 terrorist attack in 2001, it had already been overtaken by three other buildings.
In total 84 per cent of skyscrapers over 200 metres have been built since 2001 according to a report created by the Council on Tall Buildings and Urban Habitat.
Here we chart the history of the world's tallest building from early skyscrapers in New York to the 828-metre-tall Burj Khalifa in Dubai.

Park Row Building, New York City, USA (1899) ? 119 metres At the beginning of the century, the 119-metre-tall Park Row Building in New York City was the world's tallest skyscraper, a title that would remain in the city until 1974, when the Sears Tower completed in Chicago.
Originally an office block for 4,000 people, the 31-storey steel-framed early skyscraper was designed by architect R H Robertson. In the early 2000s, the building was renovated and converted into residential units.
Although the structure was the world's tallest skyscraper at the time, it was not the world's tallest building. It is considerably shorter than Ulm Minster cathedral in Germany, which rises to 161 metres.

Photo courtesy of Singer
Singer Building, New York City, USA (1908) ? 187 metres
In 1908, the B...