The Seven Wonders of the World

The Seven Wonders of the World (or the Seven Wonders of the Ancient World) refers to remarkable constructions of classical antiquity. 

The Greek conquest of much of the known world in the 4th century BC gave Hellenistic travelers access to the  civilizations of the Egyptians, Persians and Babylonians. Impressed and captivated by the landmarks and marvels of the various lands, these travelers began to list what they saw. Such a list of these places made it easier to remember them. 

Scope of the lists to seven entries was attributed to the special magical meaning of the number. Geographically, the list covered only the sculptural and architectural monuments of the Mediterranean and Middle Eastern regions, and then thought to encompass the "known" world for the Greeks. Hence, extant sites beyond this realm were not considered as part of contemporary accounts.

The primary accounts, coming from Hellenistic writers, also heavily influenced the places included in the wonders list. Five of the seven entries are a celebration of Greek accomplishments in the arts and architecture (the exceptions being the Pyramids of Giza and the Hanging Gardens of Babylon).

Among all, the Of Antipater's wonders, the only one that has survived to the present day is the Great Pyramid of Giza. The existence of the Hanging Gardens has not been proven, although theories abound. Records and archaeology confirm the existence of the other five wonders. The Temple of Artemis and the Statue of Zeus were destroyed by fire, while the Lighthouse of Alexandria, Colossus, and tomb of Mausolus were destroyed by earthquakes. Among the artifacts to have survived are sculptures from the tomb of Mausolus and the Temple of Artemis in the British Museum London.

Egypt - The only remaining of the actual 7 wonders of the world.

It is the oldest of the 7 Wonders of the Ancient World, and the only one to remain largely intact. It is believed the pyramid was built as a tomb for fourth dynasty Egyptian Pharaoh Khufu (Cheops in Greek) and constructed over a 20-year period concluding around 2560 BC. The Great Pyramid was the tallest man-made structure in the world for over 3,800 years. Originally the Great Pyramid was covered by casing stones that formed a smooth outer surface; what is seen today is the underlying core structure.

Ref : Wikipedia