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.