Many countries have applied vaccine passports to track citizens’ Covid-19 vaccination history, making it convenient for them to enter and exit. According to the World Tourism Organization (UNWTO), applying vaccination certification is an important tool to respond to the pandemic and restart safe international travel. Belize : Travelers who have been vaccinated against Covid-19 can now visit Belize without quarantine. Vaccine passports must be valid for at least 2 weeks prior to entry. In addition, travelers can also present a negative test for Covid-19 within 96 hours before entry (48 hours with the rapid test). Each rapid test on arrival at the airport costs about 1.1 million VND. Visitors come Ecuador , including the Galápagos Islands, are allowed entry if they carry a complete certificate of vaccination. Persons aged 2 years and older who do not have a vaccine passport must have a Covid-19 negative test certificate, confirmed within 3 days before arriving in this South American country. A negative test for Covid-19 must be taken within 96 hours before visiting the Galápagos Islands. Mandatory quarantine in Estonian will be exempted for guests who have been vaccinated. Visitors will be required to provide vaccination records including manufacturer information and vaccine batch number in English, Russian or Estonian languages. Those who have tested negative for Covid-19 within 6 months before entry are also not required to go through quarantine. Republic of Cyprus : From May 10, vaccinated travelers from 65 countries, including the US and UK, will not need to go through quarantine nor test for Covid-19 in this island nation. Visitors need to upload their vaccination certificate to the country’s system before entering the country. Georgia : International visitors can enter the country by air if they can prove they have been vaccinated against Covid-19. The country is still banning entry via land and water. There are separate entry rules for unvaccinated travelers based on their address. Georgia requires all travelers who have traveled through the UK 2 weeks before entry to undergo a 12-day quarantine. Greek now open to vaccinated travelers from EU member states. In addition, some travelers with vaccine passports from the UK, USA, Serbia, Israel, UAE, Iceland, Liechtenstein, Norway, Switzerland, are also allowed to enter. These travelers do not need to be quarantined or tested for Covid-19. Land, air and sea transportation of Guatemala Open traffic to stimulate international tourism. Visitors can visit the country if they have a negative test for Covid-19. In addition, visitors are also allowed to enter the country if they have a valid vaccination certificate at least 2 weeks before the trip. Iceland: According to the Icelandic government, from June 1, less stringent border quarantine measures will be applied to citizens of countries identified as low-risk areas. Visitors will skip the tests if they present an approved, digital or paper vaccination certificate in English, Icelandic, Danish, Norwegian, Swedish. Iceland is the first country in the EU/Schengen region to allow entry to vaccinated passengers from anywhere in the world. Poland quarantine is not required for people coming from countries in the Schengen area, having negative results for Covid-19 within 48 hours before entry. Citizens of countries outside this area are required to quarantine. Romania loosened quarantine requirements for travelers who have been vaccinated since January 18. However, American tourists are not allowed to enter this European country. Citizens in the group of countries allowed to enter Romania will be exempted from isolation and testing within 10 days after receiving the last dose of the vaccine. According to Lonely Planet

Ancient Mayan civilization simulated on a 3D model. The laser survey showed that in a mountainous region north of Yucatán, called Puuc, the Mayans built remarkable structures, including artificial reservoirs, more than 1,200 stoves, several fields. ladder to cultivate … Research lead William Ringle, professor emeritus of anthropology at Davidson University in North Carolina, USA said: “It looks like this is a very prosperous area because we have all the stone houses. build. ” Furthermore, the Mayans of Puuc built four major towns dating from the Middle Ages (700 BC to 450 BC) and population centers dating from 600 to 750 AD, during the Late Antiquity period. dictionary. While these structures were recorded, laser data analysis revealed that these Puuc communities had distinct city layouts that were not seen in other Maya regions. Researchers have known of the ancient Mayan settlements of Puuc since the 1840s, but there has never been a comprehensive survey of the area so far. By calculating with laser light, a software can create a detailed 3D topographic map of ancient Mayan civilization. Researchers spent about 20 years doing basic research in the Puuc region. Analysis of the lidar maps, which encompass about 237 square kilometers, revealed 7,900 housing quarters, including on the hills, indicating that the Puuc area with a large population was concentrated mainly on the Different communities, with a few in the hinterland of Puuc. Many of these residential structures still have stone veins marking different rooms – each house has about 2-3 rooms. These details suggest that Puuc may be one of the most densely populated areas in the Maya Lowlands, an area that includes parts of modern-day Mexico, Guatemala and Belize. Despite the densely populated, it seems that the people in Puuc mainly live in peace; the communities are quite close together – usually between 5 and 10 km, but there is no evidence of any defensive structure. “There are images of warriors on some of the sculptures, but it’s not to the point where people stop themselves from the neighbors,” the researchers said. Water reservoirs A densely populated area needs a lot of water, but Puuc, like the rest of Yucatan, is mostly on limestone, a porous rock. Since there was no water or river or lake, people had to find other ways to get it. Puuc is located on a hilly and raised area, making it above groundwater level. To solve this problem, the Mayans built “chultunes”, or tanks, that were lined with mortar to collect rainwater. The Mayans also built “aguadas”, or reservoirs, with long drainage channels. Lidar’s survey revealed that some of these channels were several hundred meters long. Terraces The lidar survey also revealed evidence of an intensive and widespread rock-producing industry, consisting of quarries and 1,232 circular stoves, potentially used to sinter sandstone so that produce lime, or calcium oxide. This lime is probably used as a construction mortar and to help soften corn. “When people down there cook corn, they usually soak it in lime the night before to soften it a bit, and then they will grind it,” says Ringle. Therefore, lime is an essential commodity, even at the household level. ” The number of stoves was a surprising revelation, Ringle added. They are everywhere. And that shows that it’s a sizable industry in Puuc. Other research has shown that these stoves can be operated using very little firewood. “It tells us that people probably had the raw materials pretty close at hand, even though they didn’t burn the entire forest,” Ringle said. The lidar image also showed the first clear evidence of the ladder at Puuc, actually all north of Yucatan. Although the area has hundreds of hills, only 8 hills are terraced fields for cultivation. This shows that this practice is not popular in Puuc. The ancient Maya civilization existed for more than 2,500 years, before the people mysteriously abandoned their city. There are many theories that explain why this happens. Stories are told that the Mayans mismanaged their landscape and this led to their own destruction. This new study is contrary evidence. The study was published online April 28 in the journal PLOS One.