The webmaster at Cydonia 98 has pointed out the similarity between the shape of the ridge and a dolphin. The arrangement of the ridge, the objects and the mound are also interesting. The problem with this theory is that we have no hard evidence of Martians or extra-terrestrials. One might expect ancient ruins to be less obvious and not stand out so clearly as well. The row of objects is similar in appearance to other rows of man-made structures on earth.
People have the capability to send spacecraft to the surface of Mars.
A large part of space activities are military in nature. These activities are classified and not subject to public disclosure. Other nations and organizations may also possibly have such capabilities. If a research base were to be built on Mars, the Cydonia region would be a likely candidate. The problem with this theory is how could such an operation be kept secret.