The convention center is under construction in this 2001 photo. (Kevin Clark/TWP)

The numbers sound big: 2.3 million square feet. Enough exhibit space to fit seven 747 jets. Enough steel in its frame to build seven Eiffel Towers.

The Walter E. Washington Convention Center is 10 years old, but the going has not always been easy. While it was being built, from 1998 to 2003, other cities were plotting or building their own massive meeting halls. Now Gregory A. O’Dell, Events DC president and chief executive, who manages the city’s convention and sports businesses, says, “It’s a buyer’s market.”

Here are five things you should know about the convention center on its 10th birthday:

Nearly 10 million people have visited. The exact number was 9.9 million as of Sept. 30, 2012. They came for 1,790 events, the largest of which is the Washington Auto Show. Events DC said the “direct spending” from those visitors is $3.3 billion. In 2006, the building set a Guinness World Record for the largest sit-down dinner when it served 16,206 guests at the Alpha Kappa Alpha Sorority’s centennial dinner.

The Marriott Marquis hotel next door is key. Convention center officials have long maintained that business would have been better had the center been paired with a hotel. O’Dell said that after some hiccups they are on pace to get one by June 2014. The first client to sign up for a convention package that includes the Marriott Marquis was the Association of the United States Army, which holds one of the largest annual events at the convention center and typically brings between 30,000 and 35,000 people.

It’s a tough time to be in the convention business. Thanks to a lemming-like rush to build convention centers, the competition is driving down pricing — sometimes as low as zero.

“So much supply has been built in our industry, now that smaller cities like a Charlotte, Indianapolis, Denver all built larger convention centers, so now they’re all competing with top-tier cities and it’s become a buyer’s market,” O’Dell said. “So literally other destinations are giving away their buildings, which we won’t do.”

It’s not all bad. Once the hotel opens, D.C. convention customers will be able to reduce their transportation costs. City­CenterDC will provide nearby restaurants and shopping. For that, O’Dell said prices should come back.

National Harbor is “not really competition.”

While stakeholders in the convention center were sharing celebratory appetizers last week, the Conservative Political Action Conference was also in town — but at National Harbor in Maryland. O’Dell said the Gaylord Convention Center is “not really competition for us.”

“On scale, we have 700,000 square feet of exhibit space. They have 200,000. So they would more or less compete with the larger hotels, but they’re not going to compete with the convention center.”