Wudongde Hydropower Station, the world's seventh largest, began transmitting water power from Southwest to South China on July 31.

Tower 2 of the station was the most difficult of its kind to be built for a 500-kilovolt alternating current transmission line, from the station to the Kunbei converter station.

"I doubt the choice of this position. Even monkeys might cry while seeing it," said Zeng Lei, a section manager of China Southern Power Grid who took charge of the construction.

Even though the task was tough, the project was completed 15 days ahead of schedule. The team was proud of their engineering marvel. "It's not only a job, but also an example of the unshakable faith in every one of us," Zeng said.

Watch the video to see how the miracle happened.