Complex sentence: Ten years later, with the convention now encompassing the Hyatt Regency, the Marriott Marquis and the Hilton & Towers hotels, and in 2008 added the Sheraton Atlanta Hotel, attendance had passed the 35,000 mark and continues to grow each year.
Split into simpler sentences: Ten years later--with the convention now encompassing the Hyatt Regency, Marriott Marquis and Hilton & Towers hotels--attendance passed the 35,000 mark. In 2008 the convention added the Sheraton Atlanta Hotel, with attendance continuing to grow each year.