Hello how may I help you? Hi there, I would like to know some facts. What is the tallest building in Denver, Colorado? The tallest building in Denver is the Republis Plaza. would you like to know more? What is the tallest building in the United States? One World Trade Center is the tallest building in the United States Perfect, do you know how tall the Republis Plaza is? The Republis Plaza is 714 tall. How tall is the One World Trade Center? 1,776, and 1,792 to tip Okay, great. Thank you for your help! That is all I need. You're welcome