The Philadelphia Stock Exchange, created in 1790, was the first U.S. stock exchange. And in 1975, the exchange became the first regional exchange to trade equity options. The PHLX began as a floor-based exchange, trading via an auction market. It has evolved into a hybrid market with the AUTOM--Automated Options Market system which was introduced in 1988. AUTOM, which is still used today, was created to allow electronic delivery of option orders from member firms to the exchange floor, automatic execution of certain orders, and electronic confirmation of orders. The system has been through numerous upgrades and has changed dramatically since 1988, but is still the primary automated execution system used on the floor today. The PHLX no longer has an equities trading floor, which was once adjacent to the options floor. Equities are now traded solely electronically via the exchange. The Philadelphia Stock Exchange will most likely face more changes ahead, once its planned acquisition by Nasdaq is completed. This photo gallery takes a look at the technology and structure of the options floor, which has undergone tremendous change over the years, and will probably endure further changes with the pending acquisition.