Am Fear Liath Mòr (1900, Ben MacDhui, Scotland)

Two men were chipping for crystals on the slope of a mountain, when they suddenly became aware of a giant gray-colored ten-foot tall figure walking towards them. The figure was momentarily lost from sight in a dip on the slope, and then the witnesses became extremely terrified and ran away from the area. There is a rich history of sightings of phantasmal giants on this Scottish mountain, so much that a name has been given to the creature - Am Fear Liath Mòr or the Grey Man.
Source: ‘Mystery Animals of Britain and Ireland' by Graham J. McEwan

Merbeing (1204, Orford, East Anglia, England)

One day around 1204, some Orford fishermen caught something unusually heavy in their nets. As they pulled and pulled on the nets in an attempt to get them back on board their boats, and saw what they thought was a large creature tangled up with the rest of their catch. They were extremely surprised when they finally managed to get their catch aboard because there, in the bottom of their boat was a man staring angrily at them. He was described as being naked but with a hairy body; having a long straggly beard and the top of his head being completely bald. Attempts to speak to him failed so the fishermen restrained him and took him back to the town. The ‘merman’ was taken to Orford castle where the castle custodian, Bartholomew de Gladville, kept him prisoner. He and the jailers tried time and time again to question this ‘merman’ but the creature only uttered grunts and strange noises. They noted that when he was fed raw fish he would squeeze the water out of them into his hands and then drink it. Bartholomew de Gladville became frustrated at the creature’s silence and he had the merman tortured by hanging him upside down by his ankles. Despite this ill treatment the merman still did not (or could not?) talk and eventually his jailers gave up. Bartholomew de Gladville then took him to the nearby church but it was obvious that the creature had never seen a church service before either. One day sometime after he was first captured, the merman was taken down to the harbor. Nets had been strung across the entrance and he was set free so that he could enjoy a swim but without escaping. He made straight for the nets and easily escaped under them and headed out to sea, leaping out of the water with joy. Although he spent a little time that day in sight of the harbor, he was never seen again.
Source: 'Humanoid Encounters' by Albert Rosales & http://www.visit-orford.co.uk/articles/the-merman-of-orford

Menehune (1940s, Waimea, Kauai, Hawaii)

One day during a normal period of recess, a school superintendent by the name of George London and about forty-five middle elementary students stumbled upon a group of dwarfish beings that would be best described as Menehune (Hawaiian faeries). Details of this encounter are recounted by Reverend Kenneth W. Smith of several of the local churches, who spoke to the witnesses first-hand. From his testimony, it seems that the case might have occurred earlier than he remembers. The witnesses tell of seeing the Menehune playing around the large trees on the lawn of the parish property, which is directly across the street from where the Waimea High School is today. When the dwarves spotted the children, they stopped jumping in and out of the trees and dove under the parish house, seemingly into some kind of entrance. Local folklore holds that a tunnel runs from underneath that parish house all the way up to the Menehunes’ mountainous abode. The Menehune are usually described as being 2-3ft tall and having stout and muscular bodies covered in hair of unspecified colour or texture. They have big eyes set in their red-skinned face, partially hidden by long eyebrows. Their noses are short and thick, and they have protruding foreheads.
Source & Image Credit:  The Field Guide to Bigfoot and Other Mystery Primates by Loren Coleman, Patrick Huyghe & Harry Trumbore

Neanderthal (1939, Serra da Estrela, Portugal)

Neanderthals were a species of human that are believed to have gone extinct roughly 40,000 years ago. Some people have suggested that their continued existence may explain sightings of sasquatch and bigfoot - I beg to differ on this matter, but I have an interesting case to present to you!
An 83-year-old resident of the Portuguese mountain range by the name of Serra da Estrela recently told the website ‘http://cryptozoologynews.com’ that she witnessed a group of primitive humanoids when she was 5 years old. She and her sister (8 at the time) were in a remote area of the mountains when they saw two naked men with yellowish skin speaking a bizarre language. They then saw the men entering a cave. The following day, they decided to take their sheepdog to check out the cave, but the dog refused to go in, and kept growling at the cave. The witness’s sister wanted to go back, and they could smell smoke that was apparently coming from inside the cave.
Later that day, the witness said that they told their father about the incident, and he became angry due to apparently possessing prior knowledge about the existence of ‘original peoples’ in the area. According to the father, these people survived in small numbers and were still living in a primitive state. The father said that there were only around half a dozen individuals left.
Source: http://cryptozoologynews.com/portugal-woman-encounters-neanderthal-bigfoot/