1968 - Wal-Mart expands outside of Arkansas, opening stores in Sikekton, Mo., and Claremore, Okla.

1970 - With 38 stores open, Wal-Mart enjoys $44.2 million in sales. The company also opened its first distribution center in 1970 in Bentonville, Ark.

1972 - Wal-Mart is listed on the New York Stock Exchange. For two years before it was listed on the NYSE, shares in the company were traded over the counter, meaning that brokers directly bought and sold the stock from one another.

1977 - Illinois becomes the tenth state to have a Wal-Mart store.

1983 - The first Sam's Club, the company's first members-only warehouse store, opens in Oklahoma. The new club is setup to compete with Costco, which first opened for business customers in 1976.

1987 - Wal-Mart celebrates its 25th anniversary. After 25 years in business, the company boasts some 1,198 stores with $15.9 billion in sales that year.

1988 - The first Wal-Mart Supercenter opens in Missouri. Those stores, which now encompass some 109,000 to 220,000 square feet, contain a traditional Wal-Mart and a supermarket.

1990 - Wal-Mart becomes the number one retailer in the United States, with some $26 billion in sales. Wal-Mart also purchased grocery distributor McLane Co., which was sold to Warren Buffett's Berkshire Hathaway in 2003.

1991 - Wal-Mart opens its first international store in Mexico City. The company also continued to increase the number of Sam's Club by merging with The Wholesale Club Inc. of Indianapolis. Those 28 stores were then integrated into the Sam's Club chain.

1992 - Wal-Mart co-founder Sam Walton dies at the age of 74. His brother and Wal-Mart partner James "Bud" Walton dies three years later.

1993 - The Wal-Mart International Division is created to increase the company's ability to expand overseas.

1995 - With the opening of the first store in Vermont, Wal-Mart has stores in all 50 states.

1995 - The company's 1,995 Wal-Mart stores, 239 Supercenters, 433 Sam's Clubs and 276 international stores reached $93.6 billion in sales and employ and 675,000 people.

1996 - Wal-Mart and several other retailers file suit against Visa and MasterCard. The suit accused the credit card companies of violating antitrust laws when they forced merchants that accept Visa and MasterCard credit cards to also accept their debit cards. The lawsuits were later settled, with Wal-Mart and the other retailers receiving several billion dollars from the card companies.

1996 -- Wal-Mart opens its first stores in China.

1997 - Wal-Mart sales reach $100 billion for the first time.

1999 - With some 1.14 million employees, Wal-Mart becomes the largest private employer in the world. That same year Wal-Mart sues to stop the United Food and Commercial Workers International Union from organizing its workers. The retailer claimed the union was trespassing and harassing employees. The Arkansas Supreme Court in 2002 ruled against Wal-Mart in the case, reversing a lower court ruling.

2000 - A case filed in Indiana charges that Wal-Mart did not pay workers for overtime and off-the-clock wages they had earned. In April 2003, the case became the first such suit to be designated as class action. Jay Kennedy, a partner at the law firm handling the case, says Wal-Mart is challenging that class-action designation which may delay the scheduled start to the trial in January 2005.

2002 - Wal-Mart enjoys its biggest sales day in history -- $1.43 billion on the day after Thanksgiving.

2002 - A federal jury finds that Wal-Mart forced Oregon employees to work unpaid overtime between 1994 and 1999. In the first of dozens of such lawsuits to come to trial in the United States, some 400 employees claimed managers got them to work off the clock by asking them to clean up the store after they had clocked out and by deleting hours from time records.

2004 - On July 6, Wal-Mart's lawyers appealed a ruling that granted class action status to a sex-discrimination lawsuit against the retailer that was filed in 2001. The class could include up to 1.6 million current and former female employees of the retailer -- making it the largest private civil rights case in U.S. history.

-- Compiled for the Online NewsHour by Karyn Schwartz