Mariachi musicians greeted delegations from around the world as they arrived at one of the Mexico's most luxurious beach resort areas.
It's also one of the most well-guarded resort areas in the world with soldiers on the streets and Mexico Navy vessels off shore.
The beach front setting may seem in congress for a meeting about such topics the debt crisis in Europe, poverty in developing nations and the need for sustainable agriculture and green energy.
And representatives of some non-government organizations like Christina Weller of the Catholic Agency for Overseas Development worry that the needs of poor nations may be overshadowed:
"The last two summits have been dominated by the Euro Zone crisis, by Greece. And that means there's very little agenda time for other issues."
Weller says that poverty is more than a moral blight on the world.
"It's also an economic problem. It lowers demand. That's where growth should be in those markets. If you tackle poverty, then everybody benefits."
While officials in the G20 working groups say they continue to advance work on economic development and poverty reduction, and nearby, another group is meeting concurrently and in coordination with the G20.
This group of international business leaders' meeting as the "B20" tries to work with government leaders on issues like economic development, according to the International Chamber of Commerce's Policy Director Stefano Bertasi:
"We want this to be an enduring, ongoing process of collaboration, discussion that takes place before summit, during summit and after summit."
Bertasi says that although there are areas of concern for businesses like the rise of protectionism and higher taxes, there are also many areas of mutual interest, such as the promotion of green energy.
The G20 Summit and the business leaders' "B20" meetings will both conclude Tuesday.