One of the most important aspects of programming is iterating or traversing all sorts of collections. We've come a long way since GOTO statements and C-style for-loops and most Scala programmers are already familiar with the map/filter or reduce functions. In this talk, we'll explore some further abstractions, starting with folds all the way to Monoids and Traversable Functors. The Traversable type class is without a doubt one of the hidden gems of functional programming and, because of its vast versatility, also often the answer to "How do I ?"-questions, and we'll try to gain an intuition for it. Required knowledge Basic knowledge of Scala including the mapand fold functions. Some idea of what type classes are would be best. Learning objectives Listeners should learn about the most common abstractions used for traversing and iterating over collections. It also seeks to give some more context on the relationships between related type classes of a very small subset of the cats type class hierarchy. Luka Jacobowitz is a functional programmer in love with finding great abstractions to engineering problems. He's also a maintainer of several typelevel projects, including Cats and OutWatch and seeks to make learning of pure functional programming as easy as possible.