Denmark's "Little Mermaid" statue is one of the biggest attractions in the capital with busloads of tourists posing next to it and having their pictures taken.

But later this week, the main center of attention will shift to a convention centre a ten minutes' drive away from the city center. 

Here at the Bella Convention Center, U.S. President Barack Obama will lead heads of state in supporting their cities' bid to host the 2016 Olympic Games.

Obama and his wife Michelle are leading the delegation from Chicago which is competing with three other cities — Madrid, Rio de Janeiro and Tokyo — to host the Summer Games.

Danish police say they are ready, putting in place massive security preparations ahead of the arrival of world leaders including: Spain's King Juan Carlos who will be backing Madrid's bid, Brazilian President Luis Inacio Lula da Silva who will be part of the Rio team, and newly elected Japanese Prime Minister Yukio Hatoyama who will be supporting Tokyo.

Terrorists remain the top threat to the city's security when it hosts the world leaders.

Each of the cities will make a presentation on Friday to the IOC membership who will then cast their votes the same day.

The contest has been seen by Olympic observers as one of the closest ever with no clear front runner. 

The U.S. President's presence in Copenhagen had long been a point of speculation, with Japanese Olympic officials fearing the 'Obama factor' and Brazilian officials saying his absence from the session would boost the other cities' chances.
 
Victory brings not only the Summer Games but enormous prestige, a public relations boost and potential economic and development benefits.