The first trucks commonly in use were steam wagons from the mid-19th century. Roads designed for horse-drawn carriages meant the trucks were normally limited to short haul journeys. The end of the 19th century saw the first internal combustion engine trucks, but it was in the 20th century that modern-day trucking took off. Diesel engines were beginning to be widely used from the 1920s onwards, and investment in road networks allowed for longer journeys. While many are used for commercial purposes, the military also makes use of many different types of trucks, from troop and vehicle transports, to the transportation of key resources such as fuel and ammunition for maintaining supply lines. Trucks with all-terrain capability and four or six-wheel drive are also sought after for crossing challenging landscapes.