Full of beauty, happiness and a healthy love of life, the Bulgarian   festivals and customs date back to old time when man tried to live in peace with nature. The merriest and richest festivals are Christmas and the New Year, when the socalled "sourvakari" makes the round of house with wishes for health and wealth. Other main festivals include "ladouvane" -- a holiday for young girls on New Year's Day or Midsummer Day (24th June), Shrovetide and Mummers' Games which mark the start of spring, and "lazrouvane" -- a traditional festival for love and family, health and richness.And among them, the widely popular and typical Bulgarian customs and festivals are "martenitsas" and rosepicking. Every year on March 1st, the Bulgarians give each other "martenitsas" -- a small doll made of white and red strings, a symbol of the beginning of spring, health and happiness. In late May and early June every year, the rosepicking season starts in the Valley of Roses which is between the Balkan Range and the Sredna Gora Mountains. Rosepicking starts at dawn, before sunrise and before the pleasant smell of the rose has disappeared. The Bulgarian rose produces 70 percent of the world's rose oil which is used by the very wellknown perfume   company as a basic element of its products. This is the time of the Festival of Roses, celebrated with carnivals, happy activities, folk songs and dances in Karlovo and Kazanluk on the first Sunday in June. The author of this passage intends to   _  .
let us know some knowledge of Bulgarian culture tell us the differences between customs and festivals explain the connection between customs and industry find the origin of the Bulgarian customs