One Shell Plaza is a 50-story, 1.6 million-SF office building that stands at 1,000 feet (including antennae). The 49th floor offers dining, entertainment, and meeting facilities. This building is clad in travertine and tapers upward from a landscaped marble plaza. It was the tallest concrete building in the world at the time it was built and is still the world’s tallest lightweight concrete structure.