3 . In the 1960s, while studying the volcanic history of Yellowstone National Park, Bob Christian-sen became puzzled about something that, strangely, had not troubled anyone before he couldn’t find the park’s volcano. It had been known for a long time that Yellowstone was volcanic in nature—that is what accounted for all its hot springs and other steamy features. But Christian-sen couldn’t find the Yellowstone volcano anywhere.

Most of us, when we talk about volcanoes, think of the classic cone(圆锥体)shapes of a Fuji or Kilimanjaro, which were created when erupting magma(岩浆)piled up. These can form remarkably quickly. One day in 1943, a Mexican farmer was surprised to see smoke rising from a small part of his land. In one week he was the confused owner of a cone five hundred feet high. Within two years it had topped out at almost fourteen hundred feet and was more than half a mile-across. Altogether there are some ten thousand of these volcanoes on Earth, all but a few hundred of them extinct. There is, however, a second less known type of volcano that doesn’t involve mountain building. These are volcanoes so explosive that they burst open in a single big crack, leaving behind a vast hole, the caldera(火山口).Yellowstone obviously was of this second type, but Christian-sen couldn’t find the caldera anywhere.

Just at this time NASA decided to test some new high-altitude cameras by taking photographs of Yellowstone. A thoughtful official passed on some of the copies to the park authorities on the assumption that they might make a nice blow-up(放大的照片)for one of the visitors’ centers. As soon as Christian-sen saw the photos, he realized why he had failed to spot the caldera: almost the whole park—2.2 million acres -was a caldera. The explosion had left a hole more than forty miles across-much too huge to be seen from anywhere at ground level. At some time in the past Yellowstone must have blown up with violence far beyond the scale of anything known to humans.

6 . For those looking to explore these natural wonders, all around the world there are volcanoes you can get up close to.

Vesuvius, Italy

Obviously the most famous volcano in the world, Vesuvius is considered currently dormant(休眠的), but that doesn't mean that it won't erupt at some point.Visiting Vesuvius is   more about Mount Vesuvius's past, particularly the destruction of Pompeii in A.D. 79. Though the volcano.seems harmless, the destruction of Pompeii was during a dormant phase of Vesuvius as well.

Elevation(海拔): 4,203ft

White Island, New Zealand

Making headlines recently for an eruption that killed at least five people, White Island, which is uninhabited, is usually a popular tourist attraction. It is also central to New Zealander culture,playing an important role in Maori legends. To access the island, one must take a boat tour, and then one can hike.

Elevation: 1,053 ft

Kilauea, Hawaii

The most active volcano in the world is in Hawaii where volcanoes hold local cultural legends.Nearby is also the Thurston Lava Tube which can be visited, as well as the surrounding lush jungles. The volcano is located on the Big Island, so visiting other attractions, such as Honolulu is a good choice.

Elevation: 4,009 ft

Sakuraji'ma, Japan

Less than 5 miles away from the city of Kagoshima, Sakurajima erupts almost every day.

Visiting the area is very easy, with ships leaving the city every 15 mins. Once there, Visitors can take a hike or visit the observatory, which is the closest spot to safely view the eruption. The lava has created interesting produce, including the world's largest carrot and the smallest orange.

Elevation: 3,665 ft

7 . Washington, D.C. Bicycle Tours

Cherry Blossom Bike Tour in Washington, D.C.

Duration: 3 hours

This small group bike tour is a fantastic way to see a world-famous cherry trees with beautiful flowers of Washington, D.C. Your guide will provide a history lesson about the trees and the famous monuments where they blossom. Reserve your spot before availability — the cherry blossoms—disappear!

Washington Capital Monuments Bicycle Tour

Duration: 3 hours (4 miles)

Join a guided bike tour and view some of the most popular monuments in Washington, D.C. Explore the monuments and memorials on the National Mall as your guide shares unique facts and history at each stop. Guided tour includes bike, helmet, cookies and bottled water.

Capital City Bike Tour In Washington, D.C.

Duration: 3 hours

Morning or Afternoon, this bike tour is the perfect tour for D. C. newcomers and locals looking to experience Washington, D.C. in a healthy way with minimum effort. Knowledgeable guides will entertain you with the most, interesting stories about Presidents, Congress, memorials, and parks. Comfortable bikes and a smooth tour route(路线) make cycling between the sites fun and relaxing.

Washington Capital Sites at Night Bicycle Tour

Duration: 3 hours (7miles)

Join a small group bike tour for an evening of exploration in the heart of Washington, D.C. Get up close to the monuments and memorials as you bike the sites of Capitol Hill and the National Mall. Frequent stops are made for photo taking as your guide offers unique facts and history. Tour includes bike, helmet, and bottled water. All riders are equipped with reflective vests and safety lights.

8 . Amsterdam is most famous for its artistic heritage. This tradition is proudly on display in the Rijksmuseum (translates as State Museum). Once you’ve taken in all that has to offer, artists, history fens, and families shouldn’t pass up the chance to visit the Van Gogh Museum —containing around 700 paintings and drawings by Vincent and other artists, including Gauguin, Monet, and Toulouse-Lautrec.

Amsterdam is also home to the Anne Frank Museum, where Anne hid with her family during the Nazi occupation of the Netherlands. On a lighter note, taking a canal cruise through its extensive waterways is a rewarding way to see the Dutch capital.

Art lovers get their tickets at:

♦♦ The Van Gogh Museum Rijksmuseum Museum het Rembrandthuis

Food and drink

Cheese lovers love Amsterdam. You can find an excuse to eat cheese at any time of the day here. Gouda is Holland’s favorite, developing a more intense flavor the longer it’s aged. Find a selection at the markets, try a cheeseboard at dinner time, or just order cubes with mustard for dipping to accompany a drink. When you’re hungry for non-cheese food groups, you’ll find Michel in-starred restaurants, vegetarian, and organic restaurants that accompany an array of global cuisine. For old-fashioned and modern Dutch food, try these Amsterdam restaurants: Moeders, Haesje Claes, Loctje, Greetje, and De Silveren Spiegel.

Don’t leave without tasting:

♦♦ Patat (hot chips with toppings), Stroopwafel (waffle cookie), Chocomel (chocolate milk)

Amsterdam Fast Facts

Approximate flight times:

♦♦NYC/ New York 7 hours 20 minutes, Philadelphia 8 hours, Boston 7 hours

♦♦Miami 9 hours 45 minutes, Los Angeles 10 hours 15 minutes

9 . Several things Beijingers do during wintertime

In winter, Beijing offers the city’s fun-seekers many appealing options, from royal gardens to winter resorts. Your sweet tooth and palate for fine art can also be satisfied by the abundant choices in food and art exhibitions. Here are some recommendations for you.

    1    

The Summer Palace was designed as a summer resort for the Emperor Dowager Cixi in the Qing Dynasty (1644 — 1911). Recently it has attracted thousands of tourists hoping to catch sight of the setting sun shining through the Seventeen-Arch Bridge over the frozen Kunming Lake.

    2     Eating mutton, according to Chinese traditional medicine, is able to drive out the coldness inside the body and nourish your vitality.

Surrounded by historical mansions and natural beauty, Shichahai is a must-go scenic area in Beijing. In winter, I he frozen lake becomes n giant ice rink (溜冰场), offering skating, sleigh riding and ice bicycles for beginners who don’t want to miss out on the fun.    3     You can ski, participate in snow activities, or just sit in a cozy bar and appreciate the snow-covered landscape.

It is said that a hot spring bath is good for the body and the soul.    4     Gathered in the northern part of Beijing, especially Xiaotangshan town in the Changping district, these resorts offer a great experience for a weekend getaway.

Going to a museum certainly is much nicer and warmer than staying outdoors. Luckily, cultural agencies like the National Museum and the National Art Museum recently displayed several important exhibitions.    5    

10 . Have you heard about Leap year? Leap year is a year that has 366 days instead of the usual 365. It normally occurs every four years, always on an even-numbered year. The extra day is added to our shortest month. That is the second month of the year, which in non-leap years has 28 days, two fewer than any other month.     1    

We also call Leap year the bissextile year (闰年).     2     In our calendar system there is a need for a leap year because the solar year (the time it takes the earth to go around the sun once）is actually slightly more than 365 days long. That extra day—Feb 29 every four years—helps correct the difference between our calendar and the solar calendar.

It is said that Leap year was first made part of the calendar by the ancient Roman leader Julius Caesar. His astronomers had calculated the length of the solar year to be 365 days and six hours. So Caesar declared that an extra day be added to the calendar.    3    

However, Caesar’s adjustment was not completely accurate because his astronomers’ year exceeded the true solar year by eleven minutes and fourteen seconds. By 1582, a difference of ten days had developed between the calendar year and the true solar year. To correct this error, Pope Gregory XIII ruled that every fourth year would continue to be a leap year except for century years that could not be divided evenly by 400. By this system, century years such as 1700, 1800, and 1900 were not leap years, but the year 2000 was a leap year.     4    

People born on Feb 29 celebrate their growing up a little differently from the rest of us.