"For the next six months, Italy is hosting a dinner party — and the entire world is invited to attend."

"The event, called Expo Milano 2015, is the latest World's Fair. This year's theme is "feeding the planet, energy for life." The global population is projected to pass 9 billion by 2050, and Expo organizers want to start a global conversation now about sustainability, biodiversity and food security."

"With exhibits from 145 countries over a 12-million-square-foot area, the expo is a showcase for the many cultures of food and environmental technology. Some pavilions have vertical farms. Brazil has transplanted a tropical forest. And some countries are exhibiting jointly their staple products— such as rice, coffee and cocoa."