Humans have created some incredible structures over the years. One of the most famous is the Great Wall of China, which is over 13,000 miles long and took over 2,000 years to build. Another impressive man-made structure is the Burj Khalifa in Dubai, which is the tallest building in the world, standing at 828 meters tall. The Taj Mahal in India is another architectural wonder, built entirely of white marble and taking over 20 years to complete.