According to Official Guinness Records,
The longest gingerbread was 1,052.3 m (3,451 ft 5 in) long and was achieved by Stefan Koch and Konrad Friedmann (both Germany) in Ludwigsburg, Germany, on 18 December 2009.
The gingerbread was 50 cm wide and was made from single plates of gingerbread (50 cm x 72 cm), which were glued together with a mixture of icing sugar, water and lemon juice in order to form one piece. In total it consisted of 1,700 kg flour, 1,700 kg honey, 1,000 kg walnuts, 900 kg hazelnuts, 550 litres of milk and 160 litres of cherry brandy (Kirschwasser). The record attempt was part of the charity event ‘Herzenssache’ in order to support projects for children and was given away in small pieces to the audience against a donation after the measurement had been done. It was displayed at the historic baroque garden in front of the palace in Ludwigsburg where the charity event took place. With ‘selling’ the gingerbread an amount of 89,371.83 Euros was donated.
For a complete list of 2009 records, please visit 2009 Guinness Records in Germany.