 The last Ice Age engulfed much of the world in thick oceans of ice, with Scotland being one landmass that was trapped under ice. But when did the last Ice Age end? Over a timeline of millions of years, planet Earth is on a constant cycle of warming and cooling, with ice expanding and then receding at various points. Colder periods with an abundance of ice are known as glacial periods, and warmer periods are known as interglacial periods. Earth's history is divided into giant periods of time, with our current period known as the Quaternary Glaciation, or the Pleistocene Glaciation, which began 2.5 million years ago. The Quaternary Period itself is the third and most recent period in the Cenozoic Era of the geological timescale of the planet, with the Cenozoic Era beginning 66 million years ago. The Quaternary Period itself is marked by glacial and interglacial periods, with ice expanding and then receding. The Last Glacial Period, known more commonly as the Last Ice Age, lasted from the end of the Emean Period to the end of the Younger Dryas Period, or from around 115,000 years ago to 11,700 years ago. The Last Glacial Maximum, which is the time during the Last Glacial Period that ice sheets were at their greatest extent, is thought to have occurred around 20,000 years ago. At this point, much of the northern regions of North America, northern Europe and Asia were covered by ice sheets. Global temperatures were around 11 degrees Fahrenheit, 6 degrees Celsius lower than they are today. The Last Glacial Maximum was followed by the Late Glacial Interstadial, a period of warming that took place between 14,670 and 12,890 years ago. The Younger Dryas Period put a slight spanner in the works however, as Earth returned to a brief glacial period around 12,900 to 11,700 years ago. This glacial period proved short-lived thankfully, as the Younger Dryas Period finished around 11,700 years ago, and this allowed the human population to start settling north once again. What does this mean for Scotland however? When did Scotland emerge from the ice, and when did human populations re-emerge and re-inhabit Scotland? During the Last Ice Age, Scotland was pretty much completely covered in tectonic glaciers. And any examples of human settlement prior to the Ice Age were destroyed. Using various techniques and tools, including CT scans, a team of researchers found that virtually all ice sheets had melted in Scotland around 14,000 years ago, or 12,000 BC. Even after a lot of the ice had melted, large parts still remained. This trapped water meant that sea levels were lower than today, in places such as Orkney, and some other islands are thought to have been attached to the mainland. As the ice melted, it revealed the landscape that had been forged and ground by the giant oceans of ice. A giant glacier, for instance, forged the almost 750ft deep U-shaped bed of Loch Ness for instance. Today, Loch Ness contains more water than all the lakes in England and Wales combined. One of the earliest known examples of human settlement in Scotland comes from 12,000 BC, or 14,000 years ago, as archaeologists have unearthed flint arrowheads in the town of Bigger, South Lanarkshire. Dr Alan Savill, a senior curator at the National Museum of Scotland, said in relation to the discovery that now we are able to say for certain that we had human settlement at that time in Scotland. Interestingly, he added that it must be remembered that most of the North Sea was dry land at 12,000 BC. Another discovery was made on the island of Isla, with stone implements found from 10,000 BC. Furthermore, in 2012, Scotland's oldest house was unearthed in South Queensferry, dating from 8,240 BC. The oval structure was only 7m long and had no roof. However, the walls and floor were insulated with layers of turf, moss and grasses. Vast amounts of charred hazelnut shells were also found at the site, indicating that this was an important food source for the hunter-gatherers of ancient Scotland. Scotland is also home to the world's oldest calendar, dating back 10,000 years ago to around 8,000 BC. The site at Warrenfield, Creaths, Aberdeenshire, is a series of 12 pits that mimic the phases of the moon and align with the midwinter sunrise, providing an annual astrological correction in order to maintain the link between the passage of time indicated by the moon, the asynchronous solar year and associated seasons. Project leader Vince Gaffney, Professor of Landscape Archaeology at the University of Birmingham, stated that the evidence suggests that hunter-gatherer societies in Scotland had both the need and sophistication to track time across the years. To correct for seasonal drift of the lunar year, and that this occurred nearly 5,000 years before, the first formal calendar is known in the Near East. In doing so, this illustrates one important step towards the formal construction of time and therefore history itself. Society in Scotland gradually developed over the centuries, until remains of more structured villages appear in the record. The village of Scarabrian Orkney is one for instance. Situated on the west coast of mainland Orkney, this stone-built settlement consists of 10 houses, home to stone beds and cupboards. They even had a primitive sewer system, with the houses having early forms of toilets and drains. Occupied from around 3,200 to 2,500 BC, Scarabray is one of Europe's best preserved Neolithic villages. The people who occupied Scarabray were not just hunter-gatherers. Some argued that they formed crops such as wheat and barley, and weird animals such as sheep, cattle and pigs. The village was only uncovered in 1850, when a huge storm blew the sand dune and earth that was masking the settlement. As we have seen, Scotland emerged from the last Ice Age around 14,000 years ago, and quickly developed a notable and sophisticated human population.