Rajko’s Cave is a cave in eastern Serbia, located 2.5 km from Majdanpek. With a length of 2304-meter hall is one of the longest caves in Serbia. Through Rajko’s Cave flows a river, called Rajko’s river, which starts from the Captain’s meadows after the surface flow, long 3625 m plunges below the vertical limestone slope, 50-100 m high, at the touch of crystalline schist and Upper Jurassic limestone. Appears at a level of 427.58 m. At the surface flows 22.5 and merges with Pasko’s river. Rajko’s cave is consisted of two separate parts: sinking and spring cave, and every unit has two levels, wet and dry. The cave contains a hall system, channels and corridors, and is characterized by the cave ornaments in the form of stalactites, stalagmites, columns of snow-white crystal calcite. In 2014 was finished the circular tourist trail of length of even 1410 m. Its river horizon first investigated Rajko Cvijic, and his work was continued in the seventies of the 20th century, by his assistant Lazarevic in cooperation with a group of cavers from Valjevo. R. Lazarevic has been investigated, in two terms, entire Rajko’s cave. In the first phase explored the sinking, and in the second phase the spring part of the cave.