The rectangular structure visible in the upper left portion of the photo is called the "Podium Hall." It is located east of the Augustus Temple and north of the Odeon.
Unfortunately the function of this large structure is unknown. It measures 36 x 60 ft. [11 x 18 m.]. It was built in the first half of the first century A.D. and thus would have been a new structure when the Apostle Paul visited Troas.