The Omni William Penn Hotel is a 23 floor (3 underground) hotel located at 530 William Penn Place on Mellon Square in downtown Pittsburgh, Pennsylvania. A variety of luminaries have stayed at the hotel, including John F. Kennedy. The hotel staff innovated Lawrence Welk's now famous bubble machine, and it was the site of Bob Hope's marriage proposal in 1934. The hotel has won numerous awards including being named to the "Best of Weddings 2009" list by The Knot and receiving the Editor's Choice Award in the Business Hotels category on Suite101.com.