单项选择题

A full moon was shining down on the jungle. Accompanied only by an Indian guide, the American explorer and archaeologist Edward Herbert Thompson-- thirteen hundred years after the Mayas had left their cities and made a break for the country farther north -- was riding through the New Empire that they had built for themselves, which had collapsed after the arrival of the Spaniards. He was searching for Chichen Itza, the largest, most beautiful, mightiest, and most splendid of all Mayan cities. Horses and men had been suffering intense hardships on the trail. Thompson’s head sagged on his breast from fatigue, and each time his horse stumbled be all but fell out of the saddle. Suddenly his guide shouted to him. Thompson woke up with a start. He looked ahead and saw a fairyland.
Above the dark treetops rose a mound, height and steep, and on top of the mound was a temple, bathed in cool moonlight. In the hush of the night it towered over the treetops like the Parthenon of some Mayan acropolis. It seemed to grow in size as they approached. The Indian guide dismounted, unsaddled his horse, and roiled out his blanket for the night’s sleep. Thompson could not tear his fascinated gaze from the great structure. While the guide prepared his bed, he sprang from his horse and continued on foot. Steep stairs overgrown with grass and bushes, and in part fallen into ruins, led from the base of the mound up to the temple. Thompson was acquainted with this architectural form, which was obviously some kind of pyramid. He was familiar, too, with the function of pyramids as known in Egypt/ But this Mayan version was not a tomb, like the pyramids of Gizeh. Externally it rather brought to mind a ziggurat, but to a much greater degree than the Bablyloinan ziggurats it seemed to consist mostly of a stony hill providing support or the enormous stairs rising higher and higher, towards the gods of the sun and moon.
Thompson climbed up the steps. He looked at the ornamentation, the rich reliefs. On top, almost 96 feet above the jungle, he surveyed the scene, lie counted one two-three-a half dozen scattered buildings, half-hidden in shadow, often revealed by nothing more than a gleam of moonlight on stone.
This, then, was Chichen-Itza. From its original status as advance outpost at the beginning of the great trek to the north, it had grown into a shining metropolis, the heart of the New Empire. Again and again during the next few days
Thompson climbed on to the old ruins." I stood upon the roof of this temple one morning" he writes "just as the first rays of the sun reddened the distant horizon. The morning stillness was profound. The noises of the night had ceased, and those of the day were not yet begun. All the sky above and the earth below seemed to be breathlessly waiting for something. Then the great round sun came up, flaming splendidly, and instantly the whole world sang and hummed. The birds in the trees and the insects on the ground sang a grand Te Deum. Nature herself taught primal man to be a sun worshipper and man in his heart of hearts still follows the ancient teaching."
Thompson stood where he was, immobile and enchanted. The jungle melted away before his gaze. Wide spaces opened up, processions crept up to the temple site, music sounded, palaces became filled with reveling, the temples hummed with religious adjuration. He try to recognize his task. For out there in the jungle green he could distinguish a narrow path, barely traced out in the weak light, a path that might lead to Chichen-ltza’s most exciting mystery: the Sacred Well.
Thompson believed that man is instinctively a sun-worshipper because ______.