After almost a year of speculation and rumor, city officials will unveil the details of Project Marvel — a multi-billion-dollar sports and entertainment complex — during Thursday's City Council meeting. The project includes a Henry B. González Convention Center expansion, a new hotel, much-needed upgrades to the three-decades-old Alamodome and "potentially a new arena for the San Antonio Spurs," according to the agenda item posted online last week. Even so, an array of hurdles stand in the way of the massive project, including its astronomical price tag, skeptical public attitudes and the historic designation of building scheduled for destruction.