Some common Polish customs include "Lany Poniedziałek" where young boys splash girls with water on Easter Monday, and "Andrzejki" where people try to divine their future loves on St. Andrew's Eve. Children say goodbye to winter by throwing marzanna effigies into ponds or rivers on the first day of spring. Przystanek Woodstock is a popular annual music festival held since 1995 that is inspired by the original Woodstock festival. The Copernicus Science Center in Warsaw includes hundreds of interactive science exhibits. The Wieliczka salt mine has been mined continuously for centuries and is a unique development in mining history.