Traditionally, we think of retirement as a well-deserved exit from the workforce to spend time traveling, reading and relaxing. However, many people today look for additional employment opportunities after retiring from work. In fact, AARP International says that companies around the world are making work more attractive and flexible by offering adult education, skills training and incentives to enable older people to work past retirement. Here are the top industries retirees are looking for training in to earn extra income and keep their post-retirement years active.