1 . From the deserts of Southern California to the forests of Alaska, the U. S. possesses a diversity (多样性) of nature. For most of her life, Joy Ryan never saw the scenery beyond her home state of Ohio. Then, when she was in her mid-eighties, her grandson Brad Ryan decided to take her on a journey to all of the U. S. National Parks, which took eight years to complete. At the age of 93, Grandma Joy has finally seen all 63 parks, ending her journey in the National Park of American Samoa.

“When I learned she had never seen the great wildernesses of America-deserts, mountains, oceans, I decided to intervene (干预) in some way,” Brad says. This idea inspired their first trip to the Great Smoky Mountains. However, once they were on the road, Brad realized that they could visit more parks that were nearby. Over the years, they managed to see all of the famous sights at Yosemite, the Grand Canyon, the Redwoods, and so on. But Brad values the time spent with his grandmother just as much as the amazing places they were able to visit.

Despite Grandma Joy’s older age, she was able to hike mountains. Brad regards her love for life as the key to her good health. She is grateful for each new day and is always excited for the next journey. Finally, their long journey across the U.S. came to an end with American Samoa.

“I am thankful every morning for giving me another day,” Grandma Joy shares. “And you’re your choice whether you’re going to have a rainy day or a sunny day. So, smile at everybody, and let everybody know you’re having a whale of a time.” While her tour of the U. S. has come to a close, she and her grandson are not done traveling. Next up, they have their sights set on Kenya.

2 . Consider going eastward, you will see mountains, forests and thousands of lakes, as well as wide rivers and large cities. On the 15th June I set foot off the airplane and into Calgary, Canada. I’ve never been to this side of the world before and I had some strange expectations when I could only see fields and no cityscape in view from my plane window during landing. However, as we got closer and closer to the airport the city came into view.

Phew! I breathed a sigh of relief as I’m a real city-goer. We were greeted by uncle and whisked away to the main city. The large amount of greenery in Calgary’s city makes it a completely different city to visit and I advise if anybody is around this side of the world, it’s surely an interesting visit. It not only brings us good feelings, it also makes you fall in love with this city. Despite all the things we’ve done here, the thing that blew me away the most was the Canadian woodlands and mountains just a few hours outside of Calgary. The highlight for me was risking travelling to the small town of Fernie and hiking into the woods up to a small waterfall where the water was so clear we could just drink straight from the stream.

The time away from the main city had a great holiday feel and gave me time to recover after a busy university year. It’s been a great experience being in the Canadian mountains and woodlands and it taught me the importance of just having some time for yourself! So whatever you guys are doing this summer, make sure you take some time out to relax, rest and recharge. Maybe you will get a much more comfortable trip when you jump out of the busy work.

4 . The World’s Most Amazing Caves

Humans have been drawn to caves for thousands of years. Here are four of   the world’s biggest caves.

Son Doong Cave in the remote (偏远的) forests of Vietnam holds the title of the largest cave in the world. Son Doong is a spreading network of tunnels and caves, the largest of which could contain an entire New York City block with 40-story buildings. Parts of the cave’s top have fallen down, creating vast skylights that allow life to grow to a height of hundreds of feet beneath the forest floor.

Mammoth Cave in Kentucky is the longest cave system in the world, with 426 miles explored and scientists guess another 600 miles have yet to be discovered based on measurements of air movement within the caves. Mammoth Cave has drawn visitors since the 1800s and 10 miles of underground passages are accessible to tourists today.

The longest underwater cave system in the world, Sac Actun winds (蜿蜒) more than 215 miles under Mexico’s Yucatán Peninsula. Adventurers can take a drop in the Sac Actun system through more than. 248 cenotes (天然井) — the natural swimming pools that form when sinkholes connect the surface to the underwater caves.

Veryovkina Cave is the deepest cave in the world, spreading 1.4 miles beneath the surface. It takes professionals a week to make a round journey to Veryovkina Cave. They have to brave waterfalls, tight presses and sharp drops. But the payoff is excellent — Veryovkina Cave’s end is a beautiful blue lake about 50 feet long and 25 feet wide surrounded by black rocks.

5 . Forget about “military-style ravel” during which people tend to visit as many places as possible in the least amount of time. A more relaxing and leisurely alternative, such as “Citywalk”, is becoming the norm among urban youngsters.

Unlike military-style travel, Citywalk is about wandering around a city on foot, feeling the atmosphere and finding unusual things that even a resident of the city might not have noticed before. It can be a special event where people start a journey led by tour guides or simply explore the streets.

Such walks generally avoid famous scenic spots and shopping centers, and take you to places where you can have real interactions with the local people, eat at small but authentic restaurants, and gain a deeper understanding of the city’s history and culture.

Citywalkers have shared their carefully planned routes on social media platforms, generating thousands of followers. Their posts usually include the duration of the walk, and interesting places and restaurants along the way. Some posts are more like a food tour.

Nan Xi, who recently moved from Beijing to Shanghai, said “I think Shanghai is a city perfect for Citywalk. There are big trees along the streets and shops selling different products, which is ideal for couples and friends to walk together and take photos.”

After several Citywalk experiences, she signed up for a two-and-a-half-hour Citywalk priced at 88 yuan per person. A tour guide narrated the history of the buildings and streets along the way. “If it were me walking alone, I would simply find the streets artistic, but the tour that day helped me gain a better understanding of how Western culture blends in with the local culture in Shanghai.” she said. Another surprising benefit of the walk was that she has made friends with two of her fellow walkers.

Lin Yi, a manager for an online platform for self-guided tours, thought Citywalk can help travelers learn about local culture and live as local people do, feeling the vibes of a city. “People who participate in Citywalks usually have similar tastes, and can have in-depth discussions with each other,” he said.

8 . Millions of Trip Advisor users voted New York, Chicago, Charleston and Las Vegas as the top four travel cities in the United States.

New York City

More than 50 million people visit New York City every year. The five regions of New York have some of the most easily recognized attractions in the world. Visitors whose things are tight can take a free boat from Manhattan to Staten Island for a great view of the Statue of Liberty by the sea and the Manhattan skyline.

Las Vegas, Nevada

The desert city of Las Vegas is known around the world for its casinos (娱乐场) and bright lights. Visitors stay at world-class hotels, eat at top chefs' restaurants, and usually see a spectacular show or concert.

Charleston, South Carolina

Some say Charleston is one of the most beautiful and historic places in the United States. The coastal city has a very rich history. The Civil War began at its waterfront, at Fort Sumter, which visitors can explore. But present-day Charleston has a lot to offer, too. Conde Nast Traveler voted it the number one U. S. city, for its beautiful architecture, food, and friendly people.

Chicago, Illinois

America's third-largest city offers world-class museums, great food, sporting events and symbolic architecture — including Willis Tower, America's tallest building. But what places the Midwest city above others is comedy. It's well-known for comedy shows. The Second City theater is where many famous comedians get their start, including Mike Meyers and Tina Fey.

10 . Over the last century, engineers all over the world have spared no effort to achieve the unachievable in bridge design.

Danyang-Kunshan Grand Bridge

No bridge is as long as the Danyang-Kunshan Grand Bridge in the world. The 164.8-kilometre-long bridge built in 2011 in China serves as part of the Beijing-Shanghai High-Speed Railway. The trip from Ningbo to Jiaxi ng that previously took 4．5 hours has been reduced to two, thanks to this bridge.

Rio-Niterói Bridge

Completed in 1974, the Rio-Niterói Bridge in Brazil is the second-longest bridge in all of Latin America connecting the cities of Rio and Niterói across the Guanabara Bay. The Rio-Niterói Bridge is technically known as a “box-girder (箱形梁)” bridge, made of special concrete. It receives an astonishing 140,000 (or more) vehicles per day.

Hartland Covered Bridge

The Hartland Covered Bridge is the world’s longest covered bridge. The 1,282-foot-long bridge was opened in 1901 and has been on Canada’s list of National Historic Sites since 1980． Although it was originally built without a roof, the bridge was capped with wooden materials during the repairs in 1921.

Jiaozhou Bay Bridge

The newly-built Jiaozhou Bay Bridge in China was named “world’s longest bridge over water” by Guinness Book of World Records in 2011, a title previously held by the Lake Pontchartrain Causeway. The dispute was settled when the title of “longest continuous bridge over water” was given to the causeway, with the Jiaozhou Bay Bridge receiving the title of “longest bridge over water”.