News spread quickly that Lu had built a stone-arched bridge overnight. Town people, as well as villagers from near and far, flocked to the site. The miracle also aroused the interest of Chai Rong, the fairy, and one of the "Eight Immortals ," Zhang Guolao, who wanted to test the strength of this large stone-arched bridge; so, they decided to play a practical joke on Lu.

One night, Zhang Guolao came riding a donkey with two heavy sacks containing the sun and the moon hanging from its back. Then came Chai Rong pushing a wheelbarrow loaded with the five famous mountains. Arriving together at the bridge, they met Lu and asked him whether they could cross the bridge at the same time. Lu replied proudly: "Why, such a solid bridge can surely carry the two of you? Please, go ahead." But, to Lu's astonishment, the bridge began to wobble as soon as the duo set foot on it. Sensing the seriousness of the situation, Lu jumped into the water and, with all his might, propped up half of the bridge. This way, the immortals were able to get across the bridge with their sun, moon and five famous mountains. From then on, the bridge bore the hoof prints of Zhang Guolao's donkey, the dent left by Chai Rong's knee and the grooves left behind by the wheelbarrow. Lu's handprint, where he tried to prop up the bridge, was also permanently embedded in the great structure. Today, the "imprints of the immortals" are still intact, although Lu's handprint is missing due to a partial collapse of the eastern half of the bridge.

Since Lu, Zhang Guolao and Chai Rong did not come from the same period, they could not have possibly met each other. It is also evident that one man could not have built such a large stone structure overnight. The myths and legends, however, are a reflection of the admiration felt by ordinary people for the bridge and the fond memory they cherish towards its builders. In spite of the harsh elements and natural disasters over more than 1,000 years, this large stone-arched bridge still stands tall to this very day.