Building society is a specialist savings bank. The main function of a building society is to attract savings from the public, and to lend the savings to people who wish to buy homes. Loans are made through legal agreements called mortgages. Generally, mortgages are repaid over a long period, such as 20 or 25 years. The building society holds the title deeds of the borrower's house as security until the loan is repaid. Borrowers repay the mortgage in regular amounts, generally making monthly payments. If a borrower fails to keep up regular payments, the building society may repossess the house.