What is the worlds largest rugby stadium?

In terms of capacity the Rungrado May Day Stadium in Pyongyang, North Korea is the largest staduim in the world with a capacity of 150,000. However this is mainly used for association football and cricket.

In terms of rugby, the largest capacity stadium would be:

Melbourne Cricket Ground, Australia. Seating capacity of 100,000. Although primarily used for cricket it has hosted some New South Wales Blues matches along with the Australian National Team.

Telstra Stadium, Sydney, Australia is the largest capacity stadium used solely for rugby league and Aussie Rules at 83,500.

Twickenham, London, England seats 82,000. This is solelyfor Rugby Union. So technically you could say that Twickenham is the largest sole-use Rugby Union Stadium.

also croke park in Ireland holds just over 82,000 and that hosts in ternational and club rugby teams.