returned to the Dolby Theatre, where five of the first six-season finales took place. Idol Fan Save Beginning in the top eight, American Idol introduced the Twitter-powered Idol Fan Save, similar to the Instant Save first introduced in another show The Voice. At some point during every show, the two contestants who received the lowest votes from the previous week were revealed. The bottom two contestants then performed in exactly the same format as the safe contestants. However, after the performances were completed, the viewers only had five minutes to vote by tweeting about which of the bottom two contestants should be saved; one contestant with a higher vote count will receive the save and eliminating the other. Viewers in the Eastern and Central time zones vote during the live broadcasts; due to taping delays, viewers in the Mountain and Pacific time zones are cued to vote to save contestants on the show's official Twitter account during the live East coast broadcast. Regional auditions Auditions took place in the following cities: For the New York auditions, Adam Lambert replaced Urban who took time off to be with his wife, Nicole Kidman, after the death of her father. The American Idol "Audition Bus Tour" visit the cities of: Portland, Oregon; Portland, Maine; Reno, Nevada; Columbus, Ohio; Richmond, Virginia; Albuquerque, New Mexico; Amarillo, Texas; Myrtle Beach, South Carolina; Branson, Missouri; Tallahassee, Florida; and Kansas City, Missouri. Hollywood week Hollywood Week aired in four parts over two weeks. They were filmed in late October 2014. Contestants participated in three rounds: lines of ten, groups and solos. The judges also asked some of the most notable contestants to sing for them at the beginning of the rounds, surprising many of them, but they all advanced. After Hollywood Week, contestants performed in the Showcase round in front of a live audience at the House of Blues in Los Angeles. Semi-finals The semi-finals began on February 25, 2015, and continued for four episodes. They were filmed at The Fillmore in Detroit, Michigan. They top 24 episodes were filmed February 19, 2015. The male contestants aired on Wednesday, February 25, 2015. The female contestants aired on Thursday, February 26, 2015. Those who obtained the most votes per gender group advanced onto the Top 16 and sang a song from Motown to hopefully advance further the following week. The top 16 episodes were filmed March 4, 2015, and