1 . When John Todd was a child, he loved to explore the woods around his house, observing how nature solved problems. A dirty stream, for example, often became clear after flowing through plants and along rocks where tiny creatures lived. When he got older, John started to wonder if this process could be used to clean up the messes people were making.

After studying agriculture, medicine, and fisheries in college, John went back to observing nature and asking questions. Why can certain plants trap harmful bacteria (细菌)? Which kinds of fish can eat cancer-causing chemicals? With the right combination of animals and plants, he figured, maybe he could clean up waste the way nature did. He decided to build what he would later call an eco-machine.

The task John set for himself was to remove harmful substances from some sludge (污泥). First, he constructed a series of clear fiberglass tanks connected to each other. Then he went around to local ponds and streams and brought back some plants and animals. He placed them in the tanks and waited. Little by little, these different kinds of life got used to one another and formed their own ecosystem. After a few weeks, John added the sludge.

He was amazed at the results. The plants and animals in the eco-machine took the sludge as food and began to eat it! Within weeks, it had all been digested, and all that was left was pure water.

Over the years, John has taken on many big jobs. He developed a greenhouse — like facility that treated sewage (污水) from 1,600 homes in South Burlington. He also designed an eco-machine to clean canal water in Fuzhou, a city in southeast China.

“Ecological design” is the name John gives to what he does. “Life on Earth is kind of a box of spare parts for the inventor,” he says. “You put organisms in new relationships and observe what’s happening. Then you let these new systems develop their own ways to self-repair.”

2 . Turning soil, pulling weeds, and harvesting cabbage sound like tough work for middle and high school kids. And at first it is, says Abby Jaramillo, who with another teacher started Urban Sprouts, a school garden program at four low-income schools. The program aims to help students develop science skills, environmental awareness, and healthy lifestyles.

Jaramillo’s students live in neighborhoods where fresh food and green space are not easy to find and fast food restaurants outnumber grocery stores. “The kids literally come to school with bags of snacks and large bottles of soft drinks,” she says. “They come to us thinking vegetables are awful, dirt is awful, insects are awful.” Though some are initially scared of the insects and turned off by the dirt, most are eager to try something new.

Urban Sprouts’ classes, at two middle schools and two high schools, include hands-on experiments such as soil testing, flower-and-seed dissection, tastings of fresh or dried produce, and work in the garden. Several times a year, students cook the vegetables they grow, and they occasionally make salads for their entire schools.

Program evaluations show that kids eat more vegetables as a result of the classes. “We have students who say they went home and talked to their parents and now they’re eating differently,” Jaramillo says.

She adds that the program’s benefits go beyond nutrition. Some students get so interested in gardening that they bring home seeds to start their own vegetable gardens. Besides, working in the garden seems to have a calming effect on Jaramillo’s special education students, many of whom have emotional control issues. “They get outside,” she says, “and they feel successful.”

3 . Grizzly bears, which may grow to about 2.5 m long and weigh over 400 kg, occupy a conflicted corner of the American psyche — we revere (敬畏) them even as they give us frightening dreams. Ask the tourists from around the world that flood into Yellowstone National Park what they most hope to see, and their answer is often the same: a grizzly bear.

“Grizzly bears are re-occupying large areas of their former range,” says bear biologist Chris Servheen. As grizzly bears expand their range into places where they haven’t been seen in a century or more, they’re increasingly being sighted by humans.

The western half of the US was full of grizzlies when Europeans came, with a rough number of 50,000 or more living alongside Native Americans. By the early 1970s, after centuries of cruel and continuous hunting by settlers, 600 to 800 grizzlies remained on a mere 2 percent of their former range in the Northern Rockies. In 1975, grizzlies were listed under the Endangered Species Act.

Today, there are about 2,000 or more grizzly bears in the US. Their recovery has been so successful that the US Fish and Wildlife Service has twice attempted to delist grizzlies, which would loosen legal protections and allow them to be hunted. Both efforts were overturned due to lawsuits from conservation groups. For now, grizzlies remain listed.

Obviously, if precautions (预防) aren’t taken, grizzlies can become troublesome, sometimes killing farm animals or walking through yards in search of food. If people remove food and attractants from their yards and campsites, grizzlies will typically pass by without trouble. Putting electric fencing around chicken houses and other farm animal quarters is also highly effective at getting grizzlies away. “Our hope is to have a clean, attractant-free place where bears can pass through without learning bad habits,” says James Jonkel, longtime biologist who manages bears in and around Missoula.

4 . Explorers Camp

•Full day camp for kids aged 5-13.

•Monday-Friday, July 8-26, 9am-4pm.

Week 1 | July 8-12

Week 2 | July 15-19

Week 3 | July 22-26

•Register for a single week or multiple weeks.

•Fees: $365 per week.

•The last day to cancel registration and receive a full refund (退款) is June 15.

Camp Structure

The day is divided into two thematic sessions per age group. Campers have a three-hour morning class engaging with a morning theme (9am to 12 noon) and a one-hour lunch break, followed by another three-hour class engaging with an afternoon theme (1pm to 4pm). Snack periods are held throughout the day. All campers should bring their own bagged lunch and snacks.

Camp Content

Explorers Camp organizes engaging arts, history and science-related activities in every class, and focuses on a range of topics that emphasize active learning, exploration and, most of all, fun! All camp sessions are created with age-appropriate activities that are tailored to the multiple ways that kids learn.

Camp Staff

Campers enjoy a staff-to-child ratio ranging from 1:4 to 1:7 depending on the age group. Instructors are passionate educators who are experts in their fields and have undergone training and a background check.

7 . Rome can be pricey for travelers, which is why many choose to stay in a hostel (旅社). The hostels in Rome offer a bed in a dorm room for around $25 a night, and for that, you’ll often get to stay in a central location (位置) with security and comfort.

If I had to make just one recommendation for where to stay in Rome, it would be Yellow Hostel. It’s one of the best-rated hostels in the city, and for good reason. It’s affordable, and it’s got a fun atmosphere without being too noisy. As an added bonus, it’s close to the main train station.

If you love social hostels, this is the best hostel for you in Rome. Hostel Alessandro Palace is fun. Staff members hold plenty of bar events for guests like free shots, bar crawls and karaoke. There’s also an area on the rooftop for hanging out with other travelers during the summer.

If you’re looking for cleanliness and a modern hostel, look no further than Youth Station. It offers beautiful furnishings and beds. There are plenty of other benefits, too; it doesn’t charge city tax; it has both air conditioning and a heater for the rooms; it also has free Wi-Fi in every room.

Hotel and Hostel Des Artistes is located just a 10-minute walk from the central city station and it’s close to all of the city’s main attractions. The staff is friendly and helpful, providing you with a map of the city when you arrive, and offering advice if you require some. However, you need to pay 2 euros a day for Wi-Fi.

8 . When the explorers first set foot upon the continent of North America, the skies and lands were alive with an astonishing variety of wildlife. Native Americans had taken care of these precious natural resources wisely. Unfortunately, it took the explorers and the settlers who followed only a few decades to decimate a large part of these resources. Millions of waterfowl (水禽) were killed at the hands of market hunters and a handful of overly ambitious sportsmen. Millions of acres of wetlands were dried to feed and house the ever-increasing populations, greatly reducing waterfowl habitat.

In 1934, with the passage of the Migratory Bird Hunting Stamp Act (Act), an increasingly concerned nation took firm action to stop the destruction of migratory (迁徙的) waterfowl and the wetlands so vital to their survival. Under this Act, all waterfowl hunters 16 years of age and over must annually purchase and carry a Federal Duck Stamp. The very first Federal Duck Stamp was designed by J.N. “Ding” Darling, a political cartoonist from Des Moines, lowa, who at that time was appointed by President Franklin Roosevelt as Director of the Bureau of Biological Survey. Hunters willingly pay the stamp price to ensure the survival of our natural resources.

About 98 cents of every duck stamp dollar goes directly into the Migratory Bird Conservation Fund to purchase wetlands and wildlife habitat for inclusion into the National Wildlife Refuge System — a fact that ensures this land will be protected and available for all generations to come. Since 1934, better than half a billion dollars has gone into that Fund to purchase more than 5 million acres of habitat. Little wonder the Federal Duck Stamp Program has been called one of the most successful conservation programs ever initiated.