The photos didn’t show any canals or signs of life, however. Instead, they just showed a reddish-brown desert that stretched to the horizon.
　Even so, several countries have continued to send probes to Mars. These probes have made a number of important discoveries. For example, today we know that there was once a large amount of water on this dry planet. There is a possibility that there are still lakes of unfrozen water below the planet’s surface. Some complex organic material was also found in a dirt sample, which suggests there may have been, or may still be, some form of life on Mars.
　At present, two American rovers, Curiosity and Perseverance, are in operation on the Red Planet. As their names imply, the curiosity and perseverance of human beings have led to remarkable discoveries. They now drive scientists to make further explorations. With more projects planned for the future, astronauts may be able to land on Mars within the next ten to twenty years.