Organisers will on Tuesday announce the host of the 2030 World Expo, with Rome in Italy, the Saudi capital Riyadh and South Korea's Busan contending to welcome the showpiece event held every five years.
The World Expo, which traces its history back to the 1851 Great Exhibition in London, is a months-long mega event attracting millions of visitors that aims to respond to the specific challenges of the current time.
