Chicago Zen Center was created in 1974.
Aon Center - Chicago - was created in 1973.
Chicago Cultural Center was created in 1897.
Franklin Center - Chicago - was created in 1989.
Japan Center for International Exchange was created in 1970.
Metro Chicago Information Center was created in 1990.
University of Chicago Medical Center was created in 1927.
This is kind of a vague question. The "Chicago Mercantile Exchange" has now merged with the Chicago Board of Trade and the New York Mercantile Exchange to form the "CME Group." The CME Group is the largest exchange in the world by the nominal value of it's daily trade average. As such it directly employs a lot of people in Chicago for high-skill, high-paying jobs. Additionally, the talent pool that has been created through its global leadership has also spun off a variety of trading-related companies either directly, through former employees, or indirectly by companies starting here to take advantage of the local talent pool. Additionally, when the CME went public, all of its members and many of its employees gained a large amount of wealth through seat ownership or stock options. This wealth indirectly benefits Chicago by supporting secondary service industries and investment in luxury homes, etc. Historically, the success of the Board of Trade and Merchantile Exchange enhanced Chicago's status of an agricultural and transportation center. Futures contracts made life easier for farmers, and also meant they would be bringing their grain to Chicago to sell it when the contract was due. As the exchanges expanded their products, it helped solidify Chicago's status as a grain capital and then butcher to the world. This, in turn, is a large reason why the railroads grew so large here, bringing ever-more people. The exchanges that became the CME group can't claim all the credit for Chicago's growth and success, but it's not just coincidence that the strongest city in the American Midwest also has the strongest financial exchange in the world - it's helped make Chicago's reputation in the global world of finance and kept us on the map even as manufacturing and industry moved to the Southwest and overseas.
why is Chicago a railroad center
The web address of the Chicago Cultural Center is: http://www.chicagoculturalcenter.org
It means something related to trade. Example a country that trades things/business to other countries could be said to have a mercantile relationship with each other. Rather a shopping center that deals with wholesale business.
One can find a job center in Chicago using the internet. Some websites that can help in this search for a job center include City of Chicago and FOX Chicago News.