3 . Impressive World Heritage Sites in Germany

Museum Island, Berlin

Located in Berlin’s historical centre, Museum Island houses treasures of human history in its five beautifully reconstructed museums, which delight visitors with ancient Egyptian relics. The entire complex was listed by UNESCO as a World Heritage Site in 1999.

Sanssouci Park, Potsdam

Built in the 1740s as a summer retreat for the Prussian King Frederick the Great, the palace consists of ten beautifully decorated rooms with charming gardens. A mix of truly European architecture and surroundings, Sanssouci Park was listed as UNESCO World Heritage in 1990.

Cologne Cathedral, Cologne

One of Germany’s most fascinating and extensive cathedrals, Cologne Cathedral is Germany’s most visited landmark. Due to the building’s impressive Gothic (哥特式)architecture, the shrine of the Three Wise Men, and the outstanding stained-glass windows, UNESCO declared Cologne Cathedral a World Heritage Site in 1996.

Rhine Gorge, Koblenz and Bingen

Rhine Gorge is a 65-kilometre stretch of the Upper Middle Rhine Valley. Dotted with castles, historic towns and wine-making farms, the breathtaking views and architecture, it attracts numerous visitors. In 2002 the region was added to the UNESCO list of Word Heritage Sites for its unique blend of geological, historical, and cultural elements.

4 . Five rare pink Indo-Pacific humpbacked dolphins were spotted swimming in the sea off Hong Kong, southern China. The video was filmed in the city of Shantou in Guangdong Province on April 5. The newly born In do-Pacific humpbacked dolphins are dark grey, the young ones are grey and the adults are pink. The video was provided by local media with permission.

The Indo-Pacific humpbacked dolphins known as Chinese white dolphins, or pink dolphins are first-class national protected animals and listed as “vulnerable” in the red list of threatened species by the IUCN (世界自然保护联盟). The numbers have dwindled because they are particularly vulnerable to sewage (污水) and chemicals that are dumped into the harbour daily, as well as overfishing, boat traffic and coastal development.

Dr Lindsay Porter, a senior research scientist in the University of St Andrews, has been working with local conservation group — WWF Hong Kong, to study the dolphins in the Pearl River Delta. He says the number of pink dolphins in Hong Kong has jumped by 30% in recent months. These waters, which were once the most crowded waterways in Hong Kong, have become more dolphin-friendly, ever since boat traffic was suspended in February due to the outbreak of COVID-19. “I’ve been studying these dolphins since 1993 and I’ve never seen anything like this dramatic change before, and the only thing that changed is 200 ferries stopped traveling before.

According to WWF Hong Kong, although there are about 2, 500 in the entire delta, the situation remains ugly. Still worrisome decrease in the number of young dolphins in Hong Kong’s waters has been observed. In a statement, WWF Hong Kong has advocated for the government to designate a development-free Dolphin Conservation Management Area in the western and southern Lantau waters by 2024, so that the dolphins have safe feeding and socializing habitats. It’s necessary to take a proactive approach to conserve the remaining population of the species before it’s too late.

8 . While it's not impossible for birds to fly in the rain, they usually choose not to. You may see birds fly for a few seconds in poor weather, but most of them prefer to stay put on rainy days.

Why does rain make it harder for birds to fly? You might imagine that moving through the air while being pelted by raindrops would be pretty unpleasant. However, it's not the rain itself that makes flying difficult. Instead, birds are influenced by the drop in the air pressure that comes with most rainstorms. When pressure drops, the air is less thick, which makes it harder for birds to fly. Moving through the sky in areas of low air pressure takes a lot of energy.

Most birds need to eat several times a day—rain or no rain. Luckily, most birds' feathers（羽毛）are highly waterproof（防水的）, protecting the skin beneath. Many birds can also make oil that they can spread over their feathers to further protect themselves from the rain. Most birds don't like rain. In fact, in a 2010 study, a team of researchers studied birds living in a Costa Rican rainforest. They found that the birds had higher levels of stress hormone（应激激素）on rainy days. That may not surprise you. After all, many animals feel stressed out during storms. Pet owners often find that rain and thunder make their animals nervous. Some animals are so strongly influenced by nature that they almost seem to forecast the future.

No one really knows how many birds die during a storm or series of storms. But the number is certainly higher than usual. They fly into trees or windows; they get lost over the ocean or a large lake; their food sources are made more difficult to get but, at the same time, they need more food to get warm. However, if rain continues for some time, birds will have to challenge the storm.