The military structures of the Kik n de Coc Museum and the Bastion Tunnels provide an overview of Tallinn's defensive history from medieval times to the present. Kik n de Kok is a 15th-century artillery tower that houses a museum dedicated to Tallinn's fortifications and weaponry. The nearby Bastion Tunnels date back to the 1770s. Built during Swedish rule to transport soldiers and ammunition, they were converted into bomb shelters during World War II and further modified during the Soviet period with the addition of electricity, running water, ventilation and telephones; A slow train ride gives visitors a glimpse into the evolution of the tunnels over time.