People have been smoking cannabis to get high for at least 2500 years, a new discovery has revealed.
But unlike much modern recreational use, it wasn't all fun and games.
Archaeologists found a burial site in western China where people were buried with wooden incense burners containing burnt stones. On testing, they found high levels of cannabinol, cannabidiol and cannabicyclol - all which suggest they were used to light up cannabis.
"To our excitement, we identified the biomarkers of cannabis and local chemicals related to the psychoactive properties of a plant," University of Chinese Academy of Sciences archaeology professor Yimin Yang told media.
"This is among the earliest chemical evidence of cannabis smoking."
While there is evidence cannabis has been cultivated for much longer - perhaps 6000 years - it wasn't used for its psychoactive properties, instead largely being grown as an oilseed crop. Most of it was very low in THC, the compound which gives the plant its psychoactive properties, so useless to smoke.
But the strain discovered in a cemetery found in the Pamir mountains, in Xinjiang province, was much stronger than that found in the wild.
It's not clear if ancient tokers were selectively breeding the plants to create stronger highs, or the high altitude forced plants to evolve with higher concentrations of THC.
"Humans are always going to be looking for wild plants that can have effects on the human body, especially psychoactive effects," said co-researcher Robert Spengler of the Max Planck Institute for the Science of Human History in Germany.
But despite the presence of instruments - including a harp - it's doubtful those found in Pamir were having a good time. The human remains found in the tomb also had skull perforations and broken bones, suggesting the weed was burned as part of a human sacrifice.
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"Other artifacts in these tombs suggest ritual practices," the study reads. "For example, the presence of an angular harp, an important musical instrument in ancient funerals and sacrificial ceremonies. In addition, many of the artifacts from these tombs have clear burn marks on them.
"We can start to piece together an image of funerary rites that included flames, rhythmic music, and hallucinogen smoke, all intended to guide people into an altered state of mind."
The findings were published in journal Science Advances on Thursday (NZ time).