But they got buried in the first place because the ground level of ancient cities tended to steadily rise. Settlements constantly imported food and building materials for the population, but getting rid of waste and rubbish was a much lower priority.
In many cases, people found it easier or more economical to fill obsolete constructions and build on top of them rather than remove them. So they were purposely buried by humans. Generally, what we find underground is far more valuable to us now than it was to the people who lived at the time.
Plants, living creatures, wind, rain, snow, frost, or intense sunlight all contribute to degeneration. The gradual accumulation of soil from the decay of vegetation gradually rises above ground level, and the last remnants of the house eventually become buried under a layer of soil that is slowly deepening.
To get at the archaeological evidence, archaeologists dig through these layers of built-up soil and dirt to try to understand the processes through which the layers were built up over time, and to find any artefacts buried within the layers.
Firstly, through natural processes. Old stuff might get buried by flooding which brings in silt and debris that is left behind when the water retreats. A volcano might bury a site, like at Pompeii in Italy where a whole Roman town was buried! Or perhaps a landslide caused by an earthquake or lots of rain.
Humans steal the best bits to reuse in other buildings, and erosion wears everything else to dust. So the only ancient ruins we find are the ones that were buried. But they got buried in the first place because the ground level of ancient cities tended to steadily rise.
Many people assume that most of ancient Rome has been excavated, but in fact, experts estimate that the actual number is closer to 10 percent. Most of the remaining 90 percent is buried 30 feet or so below the current street level.
There are actually many reasons why a city has to be abandoned. War, natural disasters, climate change and the loss of important trading partners to name a few. Whatever the cause, these lost cities were forgotten in time until they were rediscovered centuries later.
Most ancient cities get buried under the dust and rubble of structures that have collapsed over the centuries and millennia that followed their destruction and abandonment.
Considering that Rome once boasted 40,000 apartment buildings, 1,800 palaces, and numerous giant public buildings, of which almost nothing survives, it is clear that the ancient city is buried under its own remains.
Archaeologists use artifacts and features to learn how people lived in specific times and places. They want to know what these people's daily lives were like, how they were governed, how they interacted with each other, and what they believed and valued.
Today there are dozens of places where it's possible to descend underground and see firsthand the remnants of ancient Rome. Most are closed to the public or are only open by special permission. There are a handful of locations, however, that are open to visitors.
The tunnels are something of an open secret in Rome. Over the years, once quarrying ended, people repurposed the underground labyrinth as catacombs, for mushroom farming and as an unofficial sewer system. During World War II, people used the tunnels as bomb shelters.
Any visit of Rome starts with its fabulous Roman ruins. After all, Rome is defined by its ancient past and the traces of one of the most fascinating civilizations that have ever lived. Some of the ancient sites that can be discovered in Rome are free to visit, while others are included in different passes and cards.
The Pantheon is the oldest building in the world that's still in use today. Since the 7th century, it has been a Roman Catholic church. Built around 125 A.D. by the Roman emperor Publius Aelius Hadrianus, it was actually the third iteration of the structure.
Vatican Hill (/ˈvætɪkən/; Latin: Mons Vaticanus; Italian: Colle Vaticano) is a hill located across the Tiber river from the traditional seven hills of Rome, that also gave the name of Vatican City. It is the location of St. Peter's Basilica.
The Latins were a people with a marked Mediterranean character, related to other neighbouring Italic peoples such as the Falisci. The early Romans were part of the Latin homeland, known as Latium, and were Latins themselves.
Excavations over the past few centuries have led to discoveries that portions of Ancient Rome were up to 7 to 11 meters under current ground level (Burghignoli & Callisto, 2013).
Screens were mostly coarse-mesh screens used to recover coins and beads. Today, archeologists use several grades of mesh screen to sift through the loose soil at a dig. By using a sifter, the archeologist will find the smaller pieces of broken artifacts that otherwise might be missed.
Cities may become lost for a variety of reasons including natural disasters, economic or social upheaval, or war. The Incan capital city of Vilcabamba was destroyed and depopulated during the Spanish conquest of Peru in 1572.
By the early 19th century, the hypogeum's floor lay buried under some 40 feet of earth, and all memory of its function—or even its existence—had been obliterated.
Digging is slow, and most sites are big – so a dig can take many seasons. A single season can be anywhere from one week to a couple of months; it's rare for an excavation season to last longer than that.
Archaeologists wash, sort, catalog, and store recovered artifacts after bringing them back from the field. They analyze individual artifacts, but also may sort them into groups to see patterns.