Atlanta will host one of its biggest non-sports related conventions in years this weekend with the 2015 International Convention of Alcoholics Anonymous at the Georgia World Congress Center downtown.

More than 61,000 people from all over the nation and more than 90 countries will attend the gathering Thursday through Sunday at the convention facility and the adjacent Georgia Dome and Centennial Olympic Park. The economic impact of the meeting is expected to be about $62 million, according to the Atlanta Convention and Visitors Bureau.

Such large groups are vital to metro Atlanta. Spending on hotels, restaurants and attractions put money in the pockets of residents and helps boost the local economy.

The group is also coming at a busy time for the city this weekend, which itself is playing host to July 4th festivities at Centennial Olympic Park, the Peachtree Road Race and Atlanta Braves-Philadelphia Phillies games at Turner Field.

Convention attendees will stay in 95 hotels from the Perimeter to Hartsfield-Jackson International Airport areas, with about 3,000 housed at Georgia State University and Georgia Tech, according to the Georgia World Congress Center Authority.

About 60 percent of the conventioneers will travel to Atlanta by airplane, 400 will use scooters and wheelchairs and more than 700 have hearing aids. About 25,000 Marta passes have been sold for the convention, the GWCCA said.