One America Plaza, Modern skyscraper in Downtown San Diego, United States

One America Plaza is a 34-storey, 500 ft (152.4 m) obelisk-shaped office tower at the downtown San Diego waterfront, designed by Helmut Jahn of Murphy/Jahn Architects with KMA Architecture. Its 623,000 sq ft of floor space rise to a top that resembles the end of a Phillips-head screwdriver, a form Jahn had used a year earlier at Two Liberty Place in Philadelphia. The America Plaza trolley station occupies the ground floor between the tower and the Museum of Contemporary Art San Diego.

This building was completed in 1991 and was San Diego's tallest structure at that time. It was designed by German-American architect Helmut Jahn, who created an innovative design for the city.

The tower's name comes from the America Plaza trolley station on its ground floor, between the main building and the Museum of Contemporary Art San Diego. The 34 floors are served by Mitsubishi Electric elevators running at just over 7 m/s, the fastest in San Diego. The pointed crown, likened to a Phillips screwdriver tip, repeats a form Helmut Jahn used a year earlier at Two Liberty Place in Philadelphia.

The building sits directly next to the America Plaza trolley station, making it easy to reach by public transportation. The entrance area is at ground level and easy to access for visitors.

The building's top resembles the head of a Phillips screwdriver, a design feature the architect reused in other projects. This unusual shape makes the structure particularly recognizable from different angles around the city.