On July 20, 1969, Neil Armstrong became the first person to walk on the moon. The space suit Armstrong wore on his lunar mission has come to symbolize courage and human achievement. In 1971, the Smithsonian's National Air and Space Museum(NASM), in Washington, D.C., acquired (获得)Armstrong's suit. It stood proudly on display for visitors to admire, until there were changes in the suit's appearance. "Over time, the suit started to show signs of deterioration," Lisa Young said. Young is an objects conservator (文物修复员) at NASM. It is her job to preserve（维护）historical and cultural objects.

"Plastics are tricky to conserve," Young says. They tend to degrade (降解)over time. Neoprene is one type of plastic in Armstrong's suit. The material can turn brittle and break into tiny pieces. This would ruin the space suit. NASM, seeking ways to preserve this historical treasure, removed it from display in 2006.

What causes plastic to degrade in the first place? "Many things," Odile Madden says. Madden is a scientist in California. She explains that sunlight, water, humidity, and dust can cause plastics to degrade. "Some plastics will break down no matter what we do." Madden says.

Yet history can still be saved. Scientists have found that storing plastics in cooler temperatures, with lower humidity levels, can slow degradation. Young says Armstrong's suit is currently in storage at a temperature of 63°F and a lower relative humidity of 30%. These conditions will be maintained when Armstrong's suit returns to a museum display case in time for the 50^th anniversary of the moon landing.

Plastic degradation affects art, too. Artist Claes Oldenburg created False Food Selection in 1966.It consists of plastic food displayed in a wooden box. The plastic food used to look real. Now, some of it has flattened and yellowed. Georgina Rayner is a conservation scientist at Harvard Art Museums, in Cambridge. She says the artwork's wooden box produces an acidic (酸的) gas that eats away at the plastic. This speeds up the degradation process. But Rayner is motivated to conserve this artwork and others like it. "Plastics are a part of our history," she says. "It's important to preserve them so that future generations can understand the journey we've taken."

New Heights

The world is full of amazing lifts (电梯). Here are some of them.

The world’s fastest lift is in Shanghai Tower, in China. It travels almost as fast as a cheetah — the fastest animal on land. Whoosh!|

The Bailong Lift is the tallest outdoor lift on Earth. It is on the side of a cliff, in China. Would you want to ride in it?

The first sideways lift is in Germany. Engineers are testing it. It can travel up and down, too! Some people say it is the lift of the future.

The Burj Khalifa is the world’s tallest building. It is in Dubai — a city in Middle East. This building’s lifts are the third-fastest in the world.

An exhibition about the Grand Canal (大运河)-Paddling for a Thousand Miles-ended at the National Museum of China in Beijing on March 1.

The Grand Canal is more than 2, 500 years old. It is made up of the Beijing-Hangzhou Grand Canal, the Sui and Tang Grand Canal, and the Zhedong Canal. At nearly 3, 200 kilometers long, it is the world’s longest man-made waterway. It has influenced (影响) the development of Chinese economics and culture for hundreds of years.

Before it was built, people in ancient China used horses or simply travelled by foot to trade goods(货物). It was out of the question to send large-sized goods. After the Grand Canal connected the north and the south, business and cultural exchanges were able to develop further.

In fact, the Grand Canal played an important role in the building of the Forbidden City. Materials from different parts of the country were sent to Beijing via (通过) the canal, including bricks from Shandong and wood from Hunan. Peking roast duck even owes (把……归功于) its beginnings to the canal. People shipped white lake ducks in the south to Beijing and then fed these ducks to make Peking roast duck.

Today, people from all walks of life-businessmen, workers and drivers-often gather along the canal. They share their experiences, traditions, and culture with others. The hustle and bustle (熙熙攘攘) of the area is just something from the past, but the spirit of openness has become part of the local culture.