No one knows for certain when the first tattoos were inked. Ancient tattoos are often preserved when skin has been mummified or preserved in ice or peat.
Ötzi the Iceman, dating back to approximately 3,300BC, was found in a glacier in the Alps between Italy and Austria. Ötzi had approximately 57 carbon tattoos consisting of simple dots and lines on his lower spine, behind his left knee, and on his right ankle.
Pacific Islands
The word tattoo appears to originate from the Tahitian word tatau, meaning 'to mark'.
Most Pacific cultures believe that tattoos make a person strong or powerful both spiritually and socially enabling the body to channel its energy between human and spiritual dimensions.
Maori men tattooed their faces with fierce looking patterns and Maori women tattooed their lips and chins. These tattoos are caved into the flesh using a bone chisel, and ink is then placed in the cuts.
In Samoa the tattoo marks the ability to bear pain and is still true today and tattooing in Japan is thought to go back some ten thousand years.
Central and South America
Evidence shows that prior to the arrival of the Spanish (in 1519) tattoos and body painting was widespread and largely used for social and religious purposes (rather than just decorative). The arrival of the Spanish marked the rapid decline and extermination of many indigenous cultures, removing also the knowledge of how these looked and how they were applied.
North America
North American Indians customarily tattooed their bodies or faces or both. The usual application technique was by pricking the skin, although some California tribes added colour into scratches. Many tribes of the Arctic and Subarctic including most Eskimos (or Inuit) made needle punctures through which a strand of fibre coated with a pigment, or soot, was drawn through underneath the skin.
Central and South Africa
Traditionally the method of tattooing involved marking the design on the skin with series of black dots, which works less well with darker skins, which probably explains why tribal tattoos are not as prevalent as in other cultures. Rather than tattoos, scarification or skin painting is widely used as a way of decorating the body.
Chinese & Japanese Tattoos
From about 1600AD Japanese tattoos were used as a form of punishment. Tattooing was legalised by the occupation forces at the end of World War II. To a certain degree, tattoos still retained an image of criminality. Traditional Japanese tattoos were, for a while, associated with the yakuza, Japan's notorious mafia (although now organised criminals deliberately avoid wearing tattoos).
If you are considering Japanese Kana tattoos or Chinese character tattoos (also known as kanji tattoos), then be very careful. There are many cases where tattoo artists have got the actual meaning of the Japanese or Chinese characters wrong (deliberately, or through insufficient research), and which would obviously lead to a permanent embarrassment.
Europe
Tattooing in Europe has obviously been around for thousands of years (as seen on Ötzi the Iceman), although it was thought that Captain Cook 're-introduced' tattooing back into Europe after his voyage to the Pacific in 1769. Many sailors returned bearing souvenirs on their bodies. Since the return of this trip, tattoos have been associated with life on the sea.