Miley Cyrus and Liam Hemsworth officially called off their engagement today after battling rumors about their on-again, off-again relationship for months. Trouble first popped up for the pair earlier this year when Miley was spotted going out without her engagement ring. However, the two eventually got back together, but their road to relationship recovery was still a rocky one. Unfortunately, these two stars just couldn't work it out. Click through to relive the couple's four-year-long romance through their most memorable moments.