The Interrail Pass is a travel ticket that allows unlimited train travel across multiple countries in Europe. It is available for residents of Europe and can be used on various train services, including high-speed and regional trains. The pass is valid for a specific number of travel days within a set period, making it a flexible option for exploring different destinations. Travelers can choose from different types of passes, such as the Interrail Global Pass, which covers 33 countries, or the Interrail One Country Pass, which focuses on a single country. The pass also offers discounts on ferries and some attractions, enhancing the overall travel experience.