Let's start with a definition of a mud volcano:
Mud volcano or mud dome refers to formations created by geo-exuded mud or slurries, water and gases. There are several geological processes that may cause the formation of mud volcanoes. Mud volcanoes are not true igneousvolcanoes as they produce no lava. The earth continuously exudes a mud-like substance, which may sometimes be referred to as a "mud volcano". Mud volcanoes may range in size from merely 1 or 2 meters high and 1 or 2 meters wide, to 700 meters high and 10 kilometers wide. Smaller mud exudations are sometimes referred to as mud-pots. The largest (man made) mud volcano is " Lusi " in Java, Indonesia, which is 10 kilometres (6 mi) in diameter.(Wikipedia)
Or, in other words, it looks like a small volcano and produces a mud-like substance.
Where in Europe can you find mud volcanoes? In Russia, Ukraine, Italy and Romania. If you are driving around in this last country, head to Berca and follow the signs saying "Vulcanii Noroiosi". You have to pay a small fee at the entrance.
It is better to stay away from the mud. Lars didn't and afterwards, his shoes were completely ruined.
As you can see, there is little vegetation near the mud (or muddy) volcanoes. This is due to the salty soil. Although these mud volcanoes are not majestic, they create a spectacular lunar landscape!
You can combine your visit to the mud volcanoes with a trip in the nearby Carpathian mountains. Don't feel like staying in one of the many surrounding villages? The nearest town is Buzau, where hotels and restaurants are waiting for you. Want to know where Lars and I stayed? In our favourite place, of course! Have a look here; it takes a bit longer to reach the mud volcanoes though...