The Arch of Hadrian, also known as Hadrian's Gate, is a monumental gateway located in the historic center of Athens, Greece. It was built in the 2nd century AD by the Roman Emperor Hadrian, who was a great admirer of Greek culture. The Arch of Hadrian served both a practical and symbolic purpose. It marked the boundary between the ancient city of Athens and the new Roman city, and also served as a grand entrance to the city for visitors arriving from the east. At the same time, it celebrated Hadrian's achievements and his appreciation for Greek culture, and served as a powerful symbol of the close relationship between Rome and Athens. Today, the Arch of Hadrian is a popular tourist attraction in Athens, and is widely recognized as one of the city's most impressive ancient monuments. It is located near several other notable landmarks, including the Temple of Olympian Zeus and the Acropolis.

The Academy of Athens is one of the most prominent institutions of higher education and research in Greece. It is located in Athens, the capital city of Greece, and was founded in 1926 with the aim of promoting scientific and academic excellence in the country. The Academy of Athens is modeled after the famous Academy of Plato and is housed in a neoclassical building that was designed by the Danish architect Theophil Hansen. The building is located in the center of Athens, near Syntagma Square, and is considered one of the most important architectural landmarks in the city. The Academy is comprised of several research centers, each dedicated to a specific field of study, including humanities, social sciences, physical sciences, and life sciences. The Academy's mission is to promote research, education, and public service in these fields, and to advance the knowledge and understanding of Greece's cultural heritage and scientific contributions to the world. The Academy also plays an important role in shaping public policy and decision-making in Greece, and its members are often called upon to provide expert advice and counsel to government officials and other stakeholders. The Academy of Athens is widely recognized as a leading institution of higher learning and research in Greece, and its members have made significant contributions to a wide range of fields, including philosophy, literature, history, mathematics, physics, biology, and medicine.

The Stoa of Attalos is an ancient building located in the Agora of Athens, Greece. It was originally built by King Attalos II of Pergamon in the 2nd century BC as a gift to the city of Athens, and was used as a covered marketplace and meeting place. The Stoa of Attalos was a two-story building with a colonnade of 21 Doric columns on the ground floor and 21 Ionic columns on the upper floor. The building was about 115 meters long and 20 meters wide, and it had a central hall and several smaller rooms. During the Roman period, the Stoa of Attalos was damaged by fire and earthquakes, and it fell into disrepair. In the 1950s, the building was reconstructed by the American School of Classical Studies at Athens, using ancient building materials and techniques. Today, the Stoa of Attalos houses the Museum of the Ancient Agora, which contains exhibits on the history of the Agora and ancient Athens. The museum's collection includes pottery, coins, sculpture, and other artifacts from the ancient Greek and Roman periods.

The Panathenaic Stadium, also known as the Kallimarmaro Stadium, is an ancient stadium located in Athens, Greece. The stadium was originally built in the 4th century BC for the Panathenaic Games, a major athletic and cultural festival held in Athens every four years. The stadium was renovated in the 2nd century AD, and later underwent extensive reconstruction in the 19th century, based on its ancient design. It was used for the opening and closing ceremonies of the first modern Olympic Games in 1896, and has since been the venue for the marathon finish line in all subsequent Olympic Games held in Athens. The Panathenaic Stadium is made entirely of marble and has a capacity of approximately 50,000 spectators. The track is 204.07 meters in length and 33.34 meters in width, making it larger than a standard modern Olympic track. Today, the stadium is open to visitors, who can take a tour of the site and learn about its history and significance. The stadium also hosts various cultural and sporting events throughout the year, and is considered one of the most important landmarks in Athens.

The Temple of Hephaestus, also known as the Hephaisteion, is an ancient Greek temple located on the northwest side of the Ancient Agora of Athens. It was built in the 5th century BCE and is considered one of the best-preserved ancient Greek temples in the world. The temple was dedicated to the Greek god Hephaestus, who was the god of metalworking, blacksmiths, and craftsmen. The temple was also sometimes associated with Athena Ergane, the goddess of crafts. The Temple of Hephaestus is a Doric-style temple made of marble and limestone. It features 34 columns and a rectangular floor plan with a central cella (sanctuary) surrounded by a peristyle (a colonnade that surrounds the temple). The friezes on the temple depict scenes from Greek mythology, including the labors of Hercules and the battle between the Lapiths and the Centaurs. Despite being built over 2,400 years ago, the Temple of Hephaestus remains in excellent condition, thanks in part to its use as a Christian church in the Byzantine era. Today, it is a popular tourist attraction and an important example of ancient Greek architecture and engineering.