A listed natural sight since 1962. The serpentine ridge rises above the surrounding peneplain. The three crosses on its top were built as an expression of thanksgiving for curing a disease in 1859. Numerous rare plants grow in this area. The rarest of them is the endemit the mouse-ear chickweed which cannot be found in any other place of the world. To prevent the devastation of the Křížky nature reserve, it is strictly forbidden to enter it.
Dlouhá stoka (the Long Sewer), an artificial canal dating from 1536, can be found near Křížky. It led from Kladská through Prameny to Horní Slavkov and supplied mines with water.