Gulf Tower
Built as the headquarters for the Gulf Oil Company, the structure was designed by the firm of Trowbridge & Livingston and completed in 1932 at a cost of $10.05 million ($183.3 million today). As late as 1981 Gulf Oil employed 3,100 within the building. Now called Gulf Tower, it has 44 floors and rises 177.4 m (582 ft) above downtown Pittsburgh. The crown of the skyscraper is modeled after the Mausoleum of Halicarnassus in the style of a step pyramid. The building was listed as a Pittsburgh History & Landmarks Foundation Historic Landmark in 1973.
On June 13, 1974, a bomb was detonated on the 29th floor of the Gulf Tower. The Weather Underground Organization took credit for the attack, claiming it was in protest to Gulf Oil's involvement in the oil rich regions affected by the Angolan War of Independence.
The building was condemned following a fire on May 19, 2021, and reopened after repairs six months later.
Weather beacon
Prior to the late 1970s, the entire multistory "step-pyramid/mausoleum" structure at the top of the building was neon-illuminated, changing colors to provide a weather forecast that could be seen for many miles. This concept was developed by the building manager Edward H. Heath. He used the Gulf Oil colors to create a simplified forecast: steady blue meant colder and fair; flashing blue meant colder with precipitation; steady orange meant warmer and fair; flashing orange meant warmer with precipitation. Subsequently, in an effort to conserve energy, the weather forecasting role had been limited to the weather beacon at the pinnacle of the pyramid, which would glow blue for precipitation and red for fair weather. Although the terraced sides were once again illuminated at night (by means of spotlights), the entire pyramid structure no longer changed color with the weather (the pinnacle beacon still had that function).
| Blue – steady | – | fair & colder temperature | |
| Blue – flashing | – | precipitation & colder temperature | |
| Orange red – steady | – | fair & rising temperature | |
| Orange red – flashing | – | precipitation & rising temperature |
Starting in 2001 with the opening of PNC Park across the Allegheny River, fans began to notice that after Pittsburgh Pirates home-runs, the "beam" light flashes in celebration. Recently it was revealed that the afternoon and evening receptionist at the lobby desk was the one responsible for this fan favorite, following the games on her cabinet radio. The slogan "Flash the beam, Regina – that one's out of here!" has gained popularity among Pirates fans in the early 2000s.
The KDKA Weather Beacon, the most recent weather beacon to adorn the pyramid atop the tower, was officially dedicated on July 4, 2012. In partnership with KDKA-TV, the Gulf Tower was retrofit with a modern, automated LED weather beacon able to tell a more complete forecast than ever before. It also features holiday displays. Hearkening back to the original 1950's beacon, the entire pyramid once again changes colors at night depending on the current weather conditions:
Floor By Floor Breakdown
- 44th floor – temperature
- 43rd floor – temperature
- 42nd floor – temperature
- 41st floor – precipitation
- 40th floor – humidity
- 39th floor – wind speed
| Dark blue | – | <0 °F (−18 °C) | |
| Med blue | – | 0 to 32 °F (−18 to 0 °C) | |
| Light blue | – | 33 to 49 °F (1 to 9 °C) | |
| Amber | – | 50 to 65 °F (10 to 18 °C) | |
| Orange | – | 66 to 79 °F (19 to 26 °C) | |
| Red | – | >80 °F (27 °C) |
| Red purple | – | >.25 in (0.64 cm) | |
| Blue purple | – | ≤.25 in (0.64 cm) |
| Light green | – | <50% | |
| Dark green | – | ≥50% |
| Magenta | – | >10 mph (16 km/h) | |
| Pink | – | ≤10 mph (16 km/h) |