Fasnacht, which takes place in Basel every year near the end of February, is the biggest carnival in Switzerland. The main event lasts for three days, starting at 04:00 on the first day, but it goes on for a whole week, and is preceded by a "pre-event". Here's a link if you want to know more.
These pictures were taken on 25 February 2015. In addition to the main parades, small groups of people (from 2 people upwards) wearing costumes wander seemingly at random through the older part of Basel, playing fifes and drums. The two people in the first picture are playing fifes.