Akropolis is a decentralized pension platform, and the author claims it is their favorite mechanism. The platform allows users to create and manage pension funds in a secure and transparent manner. It provides various investment opportunities, including traditional and crypto-assets, and aims to solve pension problems by leveraging blockchain technology. The author praises Akropolis for its user-friendly interface, high security, and potential to disrupt the traditional pension system. They believe that Akropolis has the potential to address the gaps in pension provision and make retirement planning accessible to everyone.