San Antonio de los Cobres is a high-altitude town located in the Los Andes Department of Salta Province, Argentina. Situated at approximately 3,775 meters (12,385 feet) above sea level, it serves as a gateway to the Puna de Atacama region and is a key stop on the Tren a las Nubes (Train to the Clouds) railway line. The town's name, which translates to "Saint Anthony of the Coppers," reflects its historical association with copper mining in the surrounding Sierra de Cobre. Today, San Antonio de los Cobres is known for its indigenous culture, traditional weaving, and as a starting point for tourists embarking on one of the world's highest train journeys. ​ The Tren a las Nubes is a renowned tourist train that traverses the rugged terrain of the Andes, culminating at the Viaducto La Polvorilla. This impressive steel viaduct, located about 13 kilometers from San Antonio de los Cobres, stands at an altitude of 4,220 meters (13,845 feet) above sea level. Spanning 224 meters in length and reaching a height of 63 meters, the viaduct is a testament to early 20th-century engineering. Constructed between 1930 and 1932 under the direction of engineer Richard Maury, it was designed to overcome the challenging topography of the region. Today, the Viaducto La Polvorilla remains a highlight of the Tren a las Nubes experience, offering passengers breathtaking views of the Andean landscape. ​

Cairo isn’t just the capital of Egypt — it’s the pulse of the nation. A city where ancient history meets modern chaos, where the call to prayer rises above the traffic, and where every alley seems to hum with life. Home to over 10 million people, Cairo is one of the biggest and most energetic cities in the Middle East and Africa. It’s a place of contrasts — the timeless Pyramids of Giza just a short drive from bustling markets, rooftop cafés, and shiny new malls. The Greater Cairo Metropolitan Area, with more than 22 million residents, is among the most populated urban regions on Earth. Surrounded by ancient sites like Memphis, Heliopolis, and the Giza Plateau, Cairo is a living bridge between Egypt’s past and its future. The city’s origins trace back to Fustat, Egypt’s first Islamic capital founded in 641 CE, and later to 969 CE, when the Fatimid dynasty created what we now call Cairo. Through centuries — under the Ayyubids, Mamluks, and beyond — the city became Egypt’s heart of architecture, art, and learning.