The pagan observances influenced the Christian festival of All Hallows' Eve, celebrated on the same date. Gradually, Halloween became a secular observance, and many customs and practices developed. In Scotland young people assembled for games to ascertain which of them would marry during the year and in what order the marriages would occur. Many Halloween customs have become games played by children.
Immigrants to the U.S., particularly the Irish, introduced secular Halloween customs that became popular in the late 19th century. Mischief-making on this occasion by boys and young men included overturning sheds and outhouses and breaking windows, and damage to property was sometimes severe. In later years, the occasion has come to be observed mainly by small children, who go from house to house, often in costume, demanding "trick or treat" (the treat, often candy, is generally given and the trick rarely played). Since 1965, UNICEF, an agency of the United Nations, has attempted to incorporate into the Halloween observance the collection of money for the United Nations Children's Fund.
A common symbol of Halloween is the jack-o'-lantern (the name possibly was derived from that for a night watchman). It is a hollowed-out pumpkin carved in the appearance of a demonic face and with a lighted candle fixed inside. In Scotland a turnip was used, but the native pumpkin was substituted in the United States -- Encyclopaedia Brittianica, [Halloween].