Most likely the same way the Egyptians did, building a ramp. In this case they must have built up a bridging of temporary stones between the supporting columns so they are of same level, then by building ramps on both sides to buttress the whole unit, so it is strong enough to support the overhead stone being pulled up one of the ramps, when they were done and the stone was in place, they simply removed the ramps along with the temporary bridging of stones between the columns.
Chat with our AI personalities
Giant stones (e.g. the Stonehenge stones) from prehistoric times.
The major stones of Stonehenge are mostly sandstone, others are igneous rocks.
Yes.
There are several theories. see http://en.wikipedia.org/wiki/Stonehenge#Stonehenge_3_I_.28ca._2600_BC.29
Around the same time as the first three stones of Stonehenge