Downtown Miami is home to the largest concentration of international banks in the United States, and many large national and international companies. The Civic Center is a major center for hospitals, research institutes, medical centers, and biotechnology industries. For more than two decades, the Port of Miami, known as the "Cruise Capital of the World", has been the number one cruise passenger port in the world. It accommodates some of the world's largest cruise ships and operations, and is the busiest port in both passenger traffic and cruise lines.

What does downtown Miami possess more of than any other US city?