Several years ago, during my gastroenterology fellowship, I felt like I was traveling around the world without leaving the endoscopy room. In the blink of an eye, my trainers took me from Sydney to Seattle, from Los Angeles to Kyoto, or maybe they just took us for a walk around Paris or Prague in Europe.

In the field of gastrointestinal diseases, it is common to use classifications named after the author's name or the city where the expert consensus was held. Some of these classifications are still valid as they were first published, while others have been updated based on new evidence and others have been developed in recent years. This practice has resulted in a jumble of names that are sometimes difficult to remember and apply in daily practice.

However, classifications are important in clinical practice because they standardize medical reports and provide prognostic information. This summary presents a general overview of the most essential upper gastrointestinal tract (UGI) classifications alongside their interpretation and clinical relevance (Table 1).