There is no exact record of when man crossed water by a purpose-built vessel for the first time. Rock carvings describing a boat have been found in Gobustan, Azerbaijan, which are about 40000 years old. It can be assumed that our ancestors built some kind of boats or rafts much earlier, perhaps hundreds of thousands of years ago.
What we know is that man has since then crossed seas again and again and more frequently. The reasons are many: to pursue trade or to wage war, to find a new place to live – or sometimes just for the fun of it. Mankind has built ever better, larger, quicker and safer vessels and developed ever better equipment for them.
The crucial question for seafarers has always been: how to find the way? The first seafarers kept within sight of land and navigated by landmarks. The most ingenious devices and ways have since then been developed to define the course in the high seas, such as the compass based on the magnetic field of the Earth, the gyrocompass based on the rotation of the Earth, and calculating the position by astronomical observations and chronometers. Today, positioning is mostly automatic, based on a computerized satellite-based system.
For thousands of years, all ships were driven by wind or muscular strength. The first attempts at mounting a steam engine in a watercraft were made in the late 18th century, and steam-powered ships largely replaced sailing ships over the next hundred years. The last cargo carrying sailing ships left the merchant traffic by the mid-20th century. The first vessels with a combustion engine were tested in the early 19th century, but it was not until the 20th century that diesel engine driven ships could really compete with steamships. Over the past few decades, the trend has been toward more environment friendly solutions in engines and fuels and toward automated ships that could sail totally unmanned.