A volunteer photographs the fireworks during the opening of the Olympics in Beijing, Friday. (Oded Balilty/Associated Press)A volunteer photographs the fireworks during the opening of the Olympics in Beijing, Friday. (Oded Balilty/Associated Press)

China took the world stage Friday as it celebrated its first-time role as Olympic host with a stunning display to open the Games of the 29th Olympiad.

Behind the pageantry and pyrotechnics, however, there are some equally eye-catching numbers:

$40 billion — Total investment in projects related to the Games, including a new airport terminal and other infrastructure

About $5,500 — Average annual salary of a worker in Beijing

1.5 million — Estimated number of people displaced by Olympic venue construction in Beijing, according to a human rights group (China has said this number is "definitely wrong")

$15 billion — Total investment in projects related to the 2004 Athens Summer Games, final cost

$18 billion — Estimated budget for the 2012 London Games

About $1.5 million — Total cost of the 1948 London Games

$310 million — Original estimate for the cost of 1976 Montreal Olympics

$2 billion — Actual cost of the 1976 Games, tallied three decades later after all debts were paid

91,000 — Spectators watching the opening ceremonies from the Beijing National Stadium, a.k.a. the Bird's Nest

A worker draws lines on the course in the National Stadium, dubbed the Bird's Nest on April 14, 2008 in Beijing, China. China Photos/Getty Images)A worker draws lines on the course in the National Stadium, dubbed the Bird's Nest on April 14, 2008 in Beijing, China. China Photos/Getty Images)

$423 million — Cost to build the Bird's Nest

41,875 tons — Steel used in building the stadium

Four billion — Estimated television audience for opening ceremonies

80 — Heads of state expected to attend the opening ceremonies

2,008 — Drummers who pounded out the countdown to the Games

Four — Hours the opening ceremonies show lasted

$100 million — Estimated cost of the show , double the total spent on the Athens opening ceremonies four years ago

More than 30,000 — Fireworks set off in the Bird's Nest during the opening ceremony

204 — Countries sending athletes

10,708 — Athletes expected to complete

332 — Canadian athletes, compared to 639 from China and 595 from the U.S.

94 — Official air pollution level measured in Beijing Friday

Below 50 — Levels recommended by the World Health Organization for healthy air

Seven million — Tickets sold for events at Olympic venues

$900 million — Amount paid by NBC to broadcast the Games live from Beijing