The Greek conquest in the 4th century BC gave greel travelers access to the civilizations like Egyptians, Persians, and Babylonians. Impressed and captivated by the landmarks and marvels of the various lands, these travelers began to list what they saw. And the best known and earliest list of the wonders came was from a poem by Antipater of Sidon from around 140 BC. He named seven sites on his list:
I have gazed on the walls of impregnable Babylon along which chariots may race, and on the Zeus by the banks of the Alpheus, I have seen the hanging gardens, and the Colossus of the Helios, the great man-made mountains of the lofty pyramids, and the gigantic tomb of Mausolus; but when I saw the sacred house of Artemis that towers to the clouds, the others were placed in the shade, for the sun himself has never looked upon its equal outside Olympus.
— Antipater, Greek Anthology IX.58
And these are the structure in the Antipater’s Poem:
Great Pyramid of Giza
The Great Pyramid of Giza also called the Pyramid of Khufu and the Pyramid of Cheops is the oldest and largest of the three pyramids in the Giza Necropolis. it is believed to be built as a tomb for Pharaoh Khufu (Cheops). For for over 3,800 years the Great Pyramid was the tallest man-made structure in the world, its height is 146.5 metres (480.6 ft).
Hanging Gardens of Babylon
The Hanging Gardens of Babylon were built in the ancient city of Babylon, present-day Iraq, sometimes called the Hanging Gardens of Semiramis for its references to the legendary Queen Semiramis. The gardens were supposedly built by the king Nebuchadnezzar II of Babylon in around 600 BC. He constructed the gardens to please his wife, Amytis of Media.
Statue of Zeus at Olympia
The Statue of Zeus at Olympia was made by the Greek sculptor Phidias, around 432 BC on the Temple of Zeus, Olympia, Greece. The statue was dedicated to Zeus, the chief God of Greek. The statue was 12 meters (43 feet) tall. The Zeus was made of ivory and gold-plated bronze. In Zeus' right hand there was a small statue of Nike, goddess of victory, and in his left hand a golden scepter.
Temple of Artemis at Ephesus
The Temple of Artemis (Ἀρτεμίσιον, or Artemision/), also known as the Temple of Diana, was a dedicated to the Artemis, the goddess of hunt and the moon. The Tenpel’s was sited at the city of Ephesus (the modern town of Selçuk, Turkey). The temple was rebuilt three times before it was finally destroyed in 401. And today only the foundation remains.
Mausoleum of Maussollos at Halicarnassus
The Mausoleum at Halicarnassus or in other word Tomb of Mausolus (Μαυσωλεῖον τῆς Ἁλικαρνασσοῦ). The tomb was built between 353 and 350 BC at Halicarnassus (present Bodrum, Turkey) for Mausolus, a satrap in the Persian Empire and His wife who was also his sister Artemisia II of Caria. It stood approximately 45 m (148 ft) in height. The word mausoleum itself now comes to be used generically for any grand tomb.
Colossus of Rhodes
The Colossus of Rhodes was a statue of the Greek Titan Helios, the sun Titan. It was built in the city of Rhodes on the Greek island of Rhodes between 292 and 280 BC. It was constructed to celebrate Rhodes' victory over the ruler of Cyprus. Before its destruction, the Colossus of Rhodes stood over 30 meters (107 ft) high, making it one of the tallest statues of the ancient world.
Lighthouse of Alexandria
The Lighthouse of Alexandria, also known as the Pharos of Alexandria (ὁ Φάρος Ἀλεξανδρινóς). its height is around 393 and 450 ft (120 and 140 m). The tower lighthouse built between 280 and 247 BC on the island of Pharos at Alexandria, Egypt with the main purpose for guiding sailors into the harbour at night.
Beside these seven landmarks, Antipater also listed The Gate of Isthar in Babylon into the list, before he finally changed it with the Lighthouse of Alexandria. And from these seven landmarks only the Great Pyramid of Giza still remain nowday, the other six were already destroyed and leaving only the remnants like the temple of Artemis.
The seven wonders became a term for the list of magnificent landmarks or structures throughout the globe and ages. And even in the next era, with the coming of renaissance era and industrial era many structures was also erected and built, thus making a new list of the Seven Wonders in the Era.
Sources: wikipedia