Atlantic City, New Jersey:

During this time, Atlantic City was under the mayoral reign of Edward L. Bader, known for his contributions to the construction, athletics and aviation of Atlantic City. Despite the opposition of many others, he purchased land that became the city's municipal airport and high school football stadium, both of which were later named Bader Field in his honor. He led the initiative, in 1923, to construct the Atlantic City High School at Albany and Atlantic Avenues. Bader, in November 1923, initiated a public referendum, during the general election, at which time residents approved the construction of a Convention Center. The city passed an ordinance approving a bond issue for $1.5 million to be used for the purchase of land for Convention Hall, now known as the Boardwalk Hall, finalized September 30, 1924. Bader was also a driving force behind the creation of the Miss America competition.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What year was Boardwalk Hall finished?
1924