The Summer Palace in Beijing has attracted thousands of tourists this week hoping to catch sight of the setting sun shining through the Seventeen-Arch Bridge over Kunming Lake.

The spectacle only happens around the winter solstice and lasts for about 20 minutes each day at around 4 pm.

“When the sun is at its lowest point in the sky, the golden red light creates a marvelous sight through the 17 arches of the bridge,” said Jin Jiguang, a 70-year-old amateur photographer, who arrived at the spot at 8:30 am on Wednesday to secure a good vantage point ahead of the afternoon crowds.

Carrying his 20-year-old Canon 5D camera, Jin is a regular visitor to the spot. “I want to capture the best moment when each arch shares a balanced amount of light and shade,” he said. “Light shines through every arch bridge, but this one is special because of the angle as well as the pavilion and the island in the middle of the lake.”

“In the past few days, the roads near the bridge have been flooded with thousands of people in the afternoon, forming a sharp contrast with the small number of tourists in the morning,” said a sanitation worker at the Summer Palace.

Zhao Guixiang, 72, heard about the spectacle on TV and came to see it.

“With the temperature below zero today, I wouldn’t normally leave my home,” she said. “To ease congestion, the administrators of the Summer Palace have asked people to wait for a few days before coming, but people don’t want to waste such good weather.”

“I have been visiting the bridge since the 1960s. I used to swim across Kunming Lake twice every day for military training. Now I have retired, I come here once a week with my friends and walk around the lake. How come I never noticed this view before?” Zhao said.

According to Li Kun, an administrator of the Summer Palace, real-time monitoring shows that the number of visitors to the bridge peaks at about 500 around 4 pm.

To deal with the pressure of mounting tourists from 3 pm to 5:30 pm, the Summer Palace has implemented several emergency measures since Dec 6, including introducing security cordons and guard bars, putting an additional 30 members staff on patrol and increasing emergency supplies.

Built in 1750, the Seventeen-Arch Bridge is one of the most popular spots in the Summer Palace, formerly the imperial garden of the Qing Dynasty (1644-1911). The number of its arches means that when people count from either side of the bridge, the central arch is always the ninth, the favorite “lucky number” of the royal family.