Why were people from ancient Greek and Egyptian cultures so interested in the afterlife?

Because of the eternal question, "What happens to life after death"?

Explanation:

Ancient civilizations, like humans today, sought to answer this eternal question. For fear of the unknown, they created myths on which to base their religious beliefs. It is because of the fear of death that so many legends have been created, which represented a certain kind of answer to these questions. The product of all religious and mythological beliefs is this unknown of what happens to the soul after death. Thanks to myths and religious beliefs, information about the way of life, culture, art, religious beliefs of these ancient civilizations are available to us today.