A public area that is often considered the central hub of Frankfurt's modern downtown area due to its importance as a public transportation station and its central location, right between the main shopping street (Zeil) and the Rossmarkt (another public square), and just south of the 15th century Eschenheimer Turm (Eschenheim Tower). The place is named after a Baroque building ("Hauptwache") more or less in its centre. The building was constructed in 1730 to house the local city militia, as Frankfurt was an independent city at the time. When Frankfurt became part of Prussia, the building gradually lost its original function. Since 1905, it has instead been serving as a café ("Café Hauptwache"). Other attractions include the Katharinenkirche, and the Palais Thurn-und-Taxis.