The Sahara Desert, the world’s largest hot desert. About 6,000 years ago, the Sahara was a fertile land with grasslands, lakes, and forests where people lived and practiced agriculture. However, over time, the climate changed, rainfall decreased, and winds carried away fine sediments, gradually transforming the Sahara into the arid desert it is today. Notably, only about a quarter of the Sahara is sand, the rest is other terrain such as gravel plains and salt flats.
Based on rainfall, the Sahara is considered a desert, but it is the third largest in the world after the polar deserts of Antarctica and the Arctic. Although the Sahara is a tropical desert, where temperatures can reach 136°F (58°C), the nighttime temperatures are cool, creating extreme temperature changes.
The sand in the Sahara is not deep, only about 70 to 140 feet, and is formed through wind erosion. Beneath the sand are layers of bedrock and cracked clay. Several archaeological finds in the Sahara suggest that the Sahara once had a rich ecosystem, including fossilized trees, yellow glass fragments from meteorite impacts, and even shark teeth, a sign of an inland sea.
The Sahara also holds many historical secrets, such as the ancient Roman city of Tim Ghad, which was buried in sand and discovered in the 18th century, with streets and squares similar to modern-day New York.
Today, the Sahara and the Sahel to the south continue to suffer from desertification. To combat this, African countries have launched the “Green Wall” project to plant forests along West to East Africa, helping to stop the expansion of the Sahara.
In addition to the Sahara, the passage also mentions unique caves around the world. In Gibraltar, scientists discovered a cave system that was once inhabited by Neanderthals, with traces of tools and art. On the island of Flores in Indonesia, they found the skeleton of Homo floresiensis (the Hobbit) – a small ancient human species.
One of the largest caves in the world is Son Doong Cave in Vietnam, which contains ecosystems independent of the outside world, with trees, streams and even ancient stalagmites. In New Zealand, there is a famous cave with hundreds of thousands of glowing glowworms, creating a scene like in outer space.
The Sahara, the Sahel, unique caves, ocean black holes, and other extraordinary landscapes. Here is a more detailed summary:
1. **Attempts to stop the expansion of the Sahara Desert**:
– The Sahara Desert has been expanding for thousands of years, largely due to climate change and Earth cycles. Areas like the Sahel south of the Sahara are being hit hard. To prevent desertification, the **Great Green Wall** project is being implemented, in which they plant trees and develop forests to act as sand barriers and help maintain the ecosystem.
– Local people have revived more than 30,000 hectares of land using ancient techniques like “half moons” to retain water, allowing crops to grow even on dry land.
2. **Mysterious Caves**:
– **Movile Cave in Romania**: This is an ecosystem completely isolated from the outside world for 5.5 million years. There is no light and the air is full of toxic gases, but life still develops thanks to creatures that have adapted to the harsh conditions.
– **Crystal Cave in Mexico**: Located nearly 300 meters underground, giant crystals are formed here when calcium- and sulfide-rich water is heated by magma underground. These crystals have grown in a hot and humid environment for hundreds of thousands of years.
3. **Ocean black holes**:
– Giant ocean whirlpools, also known as **Eddy**, have the power of black holes in space, sucking in water and not letting it escape. They maintain a different temperature and salinity than the surrounding seawater, creating an independent environment.
4. **The Dancing Forest**:
– In the Curonian Spit, a thin strip of sand between the Baltic Sea and the Curonian Lagoon, pine trees take on strange spiral shapes. Theories suggest that this is due to unstable soil or strong winds from the sea affecting the way the trees grow.
5. **The Legendary Boiling River**:
– In the Amazon rainforest, a boiling river with temperatures reaching nearly 186°F (86°C) was thought to be a legend, but scientist Andrés Ruzo discovered it was real. Unlike other small hot springs, this river stretches for nearly 4 miles and is not associated with any nearby volcanoes.
6. **The Great Blue Hole in Belize**:
– The Great Blue Hole is a giant underwater sinkhole that was once a cave but collapsed when the sea level rose. Down below, salt and fresh water separate, creating a unique body of water with a special ecosystem and landscape.
7. **Expansion of the Sahara Desert**:
– The Sahara Desert, the world’s largest hot desert, is expanding rapidly, partly due to the Hadley circulation phenomenon that dries out the air as it descends into the tropics.
The text describes the advanced civilization of the Maya, who built complex structures such as palaces, pyramids, and agricultural systems in a tropical rainforest. They organized thousands of skilled workers to create these developments using local resources like limestone and obsidian. Despite the challenges of the environment, the Maya thrived, developing advanced agricultural techniques and a complex society known for its art, mathematics, and calendar systems.
Archaeological research has used laser scanning to reveal agricultural lowlands and evidence of the Maya’s resilience, including their ability to withstand floods and droughts. Their civilization peaked around the 6th century CE, but by 900 CE, many cities were abandoned, possibly due to resource depletion, inter-city conflicts, or prolonged drought. Some Maya cities, like Flores, persisted until the 17th century.
The Maya were skilled farmers, cultivating crops that influenced modern cuisine, and they innovated with chocolate production over 3,500 years ago. They also created a written language using codices made from fig tree bark and built impressive temples and palaces adorned with art.
Their aesthetic preferences included flat foreheads and body art, and they believed in various deities, creating wooden or clay sculptures of mythical creatures called “alexas.” The Maya viewed caves as gateways to the underworld and were pioneers in using rubber for games and building steam baths.
The text also discusses the discovery of ancient meteorites and archaeological sites like Stonehenge and Superhenge, which have yet to be fully understood. It concludes with the mention of mysterious spherical stones in Costa Rica and the Nazca Lines in Peru, showcasing the enduring mystery of ancient civilizations.
Cleopatra is often portrayed as a femme fatale, but there’s no solid evidence of her unparalleled beauty; This image was largely crafted by Hollywood. Born in Egypt, she was of Greek descent and understood the local culture, which earned her the love of the Egyptian people. Cleopatra was an intelligent ruler who promoted Egypt’s economy and international standing. To secure her power, she sought the help of Julius Caesar, disguising herself to meet him and ultimately becoming his lover and ally. Later, she impressed Mark Antony with a grand entrance, further strengthening her political ties with Rome.
However, her relationship with Antony stirred controversy in Rome, with Octavian, Antony’s rival, using propaganda to portray Cleopatra as a manipulative seductress. This tension culminated in a naval battle where Antony was defeated, leading to his retreat to Egypt with Cleopatra. Legends say she used poison to end her life when cornered by Roman forces, but the details remain uncertain. After her death, Octavian took control of Egypt and became Emperor.
Surprisingly, more time has passed since Cleopatra’s reign than between her and the construction of the Great Pyramid of Giza.
In terms of architecture, unique structures have been built in deserts, such as Earthships in New Mexico, made from recycled materials and designed for sustainability. These homes maintain comfortable temperatures through passive solar design. There are also conceptual homes like the Mirage Mirror House in California, which blends into its surroundings with mirrored surfaces.
Additionally, various remarkable desert buildings adapt to climates, like the King Abdullah Petroleum Studies Center in Saudi Arabia and the Eco Lodge in Egypt, both designed to minimize energy use.
Amidst these deserts, dangerous creatures exist, such as the jumping cholla cactus, which resembles a teddy bear but is covered in sharp needles that can easily attach to skin or clothing.
The whip scorpion, silent and fast, has long front claws, making it a formidable predator. Although it avoids sunlight due to poor eyesight, it’s actually quite harmless and often kept as a pet in glass terrariums. If it escapes, however, it can be hard to catch.
On the other hand, the Arizona bark scorpion is the most venomous in the U.S., often found in homes and yards. Its sting can cause pain akin to a bee sting, and severe allergic reactions are possible.
Traveling to Africa’s Sahara Desert, you might be surprised by its vastness, stretching from the Atlantic to the Red Sea. The Sahara is expanding, having increased in size by over 10% since the 1920s, primarily due to climate changes and human activity. This region, which receives less than 4 inches of rain annually, was once a green oasis about 20,000 years ago.
Evidence from rock art shows that Northern Africa was wetter, housing diverse wildlife. Geological studies support this, indicating that during a humid period, vegetation thrived, and lakes formed. Ancient societies flourished in this greener Sahara, but today, desertification is advancing, turning fertile land into desert as human populations grow.
The text also discusses the Missoula Flood in North America, which occurred when a massive glacier melted, creating a huge lake. The ice dam holding back this water eventually failed, resulting in a catastrophic flood that shaped the landscape, leaving behind significant geological features like the Dry Falls in Washington state.
