In Midgard, a world within the nine worlds of Norse mythology, there were many encounters between Loki and Thor with the giants. In fact, many legends of seas, sky and mountains being formed involved the bodies of giants. In fact, the question is often asked if Thor himself might have been a giant, as the question has been posed about Moses.
Jotun: Jotun also called a giant. This is the first living being, and the first of them was a Jotun called Ymir, and from Ymir was the world was created. A Jotun is a giant with superhuman strength; their homeland is Jotunheim, which is one of the nine worlds. Jotunheim is a mostly made of mountains, wilderness and dense forests. The giants mostly lives from the fish in the water, and the animals from the dense forests, because there is no fertile land...Bergermil - His name Bergelmir means "Mountain yeller" or "Bear Yeller". Bergelmir is a frost giant, and the son of Thrudgelmir and the grandson of Ymir, the first giant. Bergelmir and his wife are the only two survivors of all the giants after Ymir's death and the flood. They used a hollowed out tree trunk to sail on the flood, it was the first boat. Because of Bergelmir and his wife, the race of frost giants were able to survive and live in Jotunheim. (Sound a bit like Noah, hmm? Some say one of Noah's sons was a giant).
Source: It looked to be a routine excavation of what was thought to be a burial mound. But beneath the mound, archaeologists from the Norwegian University of Science and Technology's Museum of Natural History and Archaeology found something more: unusual Bronze Age petroglyphs...But researchers suspected there might be another reason for the choice of the hilltop when they uncovered the remains of two cremations, or rather a fire layer that also contained bits of bone. Underneath they found many petroglyphs, including eight drawings showing the soles of feet, with cross hatching. There were also five shallow depressions, Haug says. Two boat drawings and several other drawings of feet soles with toes were also found just south of the burial mound. Link between burial mound and drawings unclear. "This is a very special discovery, and we are not aware of other similar findings from Trøndelag County," she says. "The tomb might have been deliberately constructed over the petroglyphs, probably as part of funeral ritual. Based on the type of characters and especially the drawings of the foot soles, we have dated the artwork to the Bronze Age, about 1800 -- 500 BC."
Source: The "Kalevala" was a published work of 1835 that is involves Finnish National Identity. It involves a giant called Antero Vipunen who lived underground.
Source: Archaeologists have unearthed the remains of unusually large wooden monuments near a pre-Viking Age burial ground. Archaeologist Lena Beronius-Jorpeland said the colonnades were likely from the 5th century but their purpose is unclear. She called it Sweden's largest Iron Age construction and said the geometrical structure is unique. "It is a completely straight line and they have dug postholes every 20 feet (6 meters)," she said. "They have had an idea of exactly where this line is going and where to build it. It is a fairly modern way of thinking and we don't have many traces of these sorts of constructions from that time." She said the pillars are believed to have been at least 23 feet (7 meters) high (excessive, eh?). Bones found in some postholes indicate animals had been sacrificed there.
The Smoky God, or A Voyage Journey to the Inner Earth is a novel of 1908 by Willis George Emerson, which is presented as a true account of a Norwegian sailor named Olaf Jansen, and explains how Jansen's sloop sailed through an entrance to the Earth's interior at the North Pole and met with a giant race.
Ulfberht Sword: Infamous Viking swords. No one understood how this was made by the Norse so far ahead of its time, but was the technology of an older culture, learned from them? In the Saami (Laplander-Northern Scandinavian) legends, however, we might gain insight as to who taught the science. From the book Lapland Legends (tales of the Sami People): This time she sent a horde of powerful strangers with sharp weapons to make an end of the happy people. These men were tall in stature, strong, cruel, and greedy for gold, and their weapons were like those of the Roiters, were made of a shining, biting substance which was hard and cold and gleamed like moonbeams upon ice. Against these weapons, the Kobdas' magic seemed powerless. Once more, the sun-children sought shelter in the forests and among the mountains.
Source: Due to just the right conditions, ancient Funnel-Beaker Era (5500 years ago) pottery was found intact in Norway. In an interesting tie-in, the Funnelbeaker Era in Norway showed similar characteristics to stone structures found in New England -
Source: The earliest surviving reference to the term "berserker" is in Haraldskvæði, a skaldic poem composed by Thórbiörn Hornklofi in the late 9th century in honour of King Harald Fairhair, as ulfheðnar ("men clad in wolf skins"). This translation from the Haraldskvæði saga describes Harald's berserkers:
I'll ask of the berserks, you tasters of blood,
Those intrepid heroes, how are they treated,
Those who wade out into battle?
Wolf-skinned they are called. In battle
They bear bloody shields.
Red with blood are their spears when they come to fight.
They form a closed group.
The prince in his wisdom puts trust in such men
Who hack through enemy shields.
And, most people of a region have legends of giants. The Norse had their trolls. Originally trolls were giant-sized. After the introduction of Christianity, these became little beings as described in their legends.
We have something similar playing out today in population-dense areas that are showing signs of collapse, disease, and adversity such as Africa, India and China and yet they were very ancient settling places for Homo sapiens. This may be comparable to what the giant culture suffered in over-tapped resources with the coming of fast-breeding Homo sapiens and the upheaval created by "Native" people of the the world.
What happened to the giants? If they sent out their powerful men to find new lands, they likely ran into lack of breeding pools, mining might have polluted their waters and diseased them at early ages, and local infringing Native people might have driven them or killed them off. As well, the general scaling down of animals from the giant sloths, mastodons and such, provided more agile, less meaty creatures to stalk for protein sources, making the giants turn cannibal on the Homo sapiens.
There are many scenarios to consider for why they are no longer coexisting with us. But, if we look closely at our woodlands, we might realize they are still among us, only understandably cautious.