Bonaventure Hotel in Los Angeles). In the ensuing decades, the Renaissance Center expanded to join the city's restored historic art deco skyscrapers in forming the current skyline. In 1924, Detroit's Book-Cadillac opened as the world's tallest hotel (it is now a re-developed Westin Book-Cadillac Hotel). Completion of the first phase of the Renaissance Center in 1977 restored this distinction to the city. The Renaissance Center's central tower opened with a flagship hotel, the tallest in the world, and a conference center with the world's largest rooftop restaurant. As of 2012 the hotel is Marriott International's largest in the United States, with 1,298 rooms. Though it is no longer the world's tallest hotel, it remains the tallest all-hotel skyscraper in the Western Hemisphere. The Westin hotel and conference center at the Southfield Town Center is across from Lawrence Technological University. Stemming the flight of capital from the city proved difficult, however, as the suburban office market continued to grow, notably in Southfield and Troy. The Southfield Town Center, constructed from 1975 to 1989, became easy to recognize with its marque of five golden glass skyscrapers. It attracted tenants in competition with the Renaissance Center as Metro Detroit's office market continued its suburban expansion. Portman designed the Renaissance Center with interior spaces, yet secure. It quickly became a symbol of the city of Detroit. In 1996, the Renaissance Center's design changed when General Motors purchased the entire complex for its new headquarters. The $500-million makeover of the complex included a $100-million renovation of the hotel. A new front door Wintergarden (2003) provides waterfront views and expanded retail space. Prior to completion of its renovation in 2003, some had criticized its circular corridors as confusing. Construction of a lighted glass walkway now facilitates ease of navigation encircling the interior mezzanine. A pedestrian-friendly glass entry way has replaced the former concrete berms along Jefferson Avenue. The city, together with the Riverfront Conservancy, undertook another major project planned at $559-million along the Detroit International Riverfront to construct a three-mile (5 km) riverfront promenade park along the east river from Hart Plaza and the Renaissance Center to the Belle Isle bridge. Detroit Wayne County Port Authority added the Dock of Detroit (2005), a state of the art cruise ship dock on Hart Plaza near the Renaissance Center. A two-mile (3 km) extension along the west river will take the riverfront promenade park from Hart Plaza to