The annual Solothurn "Fasnacht" or carnival kicked off on Thursday in the baroque city on the banks of the river Aare.
For four days, Solothurn is known as Honolulu and sinks into colourful mayhem, honouring a tradition that is at least 500 years old.
Dirty Thursday, as the first day of carnival is known, begins at the crack of dawn. At five o'clock, the Oberchessler, or leader of the carnival, gives the signal on Friedhofplatz for the festivities to begin.
This is the go-ahead for people of all ages, dressed in nightshirts, caps and red neckerchiefs, to be as raucous as possible as they walk through the streets of the old town. With the aid of cowbells, horns and rattles, the crowd could make enough noise to wake the city's dead.
After completing a tour of the Solothurn-cum-Honolulu, the revellers are treated to a traditional breakfast of flour soup with mütschli, a special bread roll.
During the afternoon, children in fancy dress run amok in the main street and play confetti battles. They can also take part in a procession, a recent tradition that was started in 1982.
The revels then continue from the following Sunday to Ash Wednesday. The main procession takes place on Sunday from the Amthausplatz. Its start is marked by a cannon shot at exactly 31 minutes past two in the afternoon.
Nearly 40 organisations represented by colourful floats and marching bands will participate in this year's procession.
Burn Böögg burn
When the partying comes to an end on Ash Wednesday, it will have a spectacular send-off: the burning of a Böögg or monster effigy.
The crowds gather to watch this fantasy figure condemned to death by fire.
And equality of the sexes is the order of the day, as the sex of the Böögg is alternated every year.
The finale is similar to the highlight of Zurich's annual Sechseläuten festival, where a snowman-like figure is burnt.
As the Böögg becomes no more than a pile of glowing embers, the city undergoes a transformation from the exotic Honolulu to sedate Solothurn.
Solothurn joins cities like Lucerne, Basel and Bern, which also hold Fasnacht festivities in late February and early March.
The Solothurn Fasnacht runs from February 27 until March 5.
swissinfo, Faryal Mirza