In terms of sheer wonder, the Stone Age treasures of Orkney - the oldest built structures in Scotland, must qualify. Within a few square miles, mainland Orkney offers a cluster of standing stones that predate Stonehenge, a unique Stone Age village uncovered by the sea and a mysterious burial mound containing the biggest collection of Viking runic writing.
Visit at the winter solstice and see feats of alignment that inspire and astonish.
The oft-overlooked wonders of the far north include Maes Howe, the Ring of Brodgar, the Standing Stones of Stenness and Skara Brae - all designated World Heritage Sites. Skara Brae is the most visited; I'd plump for Maes Howe if forced to choose. Go to http://www.maeshowe.co.uk/ to see the webcam that shows the solstice sunset shining down the passage of Maes Howe, lighting up the back wall and the stone passage for just a few minutes around the shortest day in December till all is dark again.
Maes Howe is the finest architectural achievement of prehistoric Europe, from around 2,750BC. That predates the Great Pyramid of Giza by an estimated 300 years, Callanish by around 700 years. The chamber has corner stones like the standing stones outside at the Ring of Brodgar. Mix 'n' match from prehistory!
The chamber was opened in 1862 but nothing was inside except the biggest-ever collection of runic messages left by Vikings. It seems they broke in to find shelter during a storm in the winter of 1123. Amazingly, their epic messages are everyday, boastful, rude and funny, just like the kind we leave: "Many a woman has come stooping in here no matter how pompous", or "these runes were carved by the man most skilled in runes on the Western Ocean".
The quality of the construction and size of the sandstone blocks used, together with the precision in quarrying and stone-cutting would tax the Scottish Parliament builders. Some of the slabs still fit so well together that a knife-blade cannot be inserted between them. Estimates suggest that the Maes Howe building would have taken 39,000 man-hours.
Chambers off the main room did contain bones - but puzzled everyone because no trappings of high rank could be found. The popular conclusion locally is our Stone Age forebears buried everyone together - commoners and "kings"; a great expression of Scotland's egalitarian tradition. It also seems likely a Viking of great status was later buried here, which accounts for the absence of Stone Age artefacts, the presence of myths about a hogboon (powerful spirit) and the runic messages referring to "great treasures removed".
George Mackay Brown wrote after one solstice visit: "The most exciting thing in Orkney, perhaps in Scotland, is going to happen this afternoon at sunset. At this season, the sun is a pale wick between two gulfs of darkness. Surely there could be no darker place in the be-wintered world than the interior of Maes Howe.
"One of the light rays is caught in this stone web of death. Through the long corridor it has found its way; it splashes the far wall of the chamber. The illumination lasts a few minutes, then is quenched.
"Winter after winter I never cease to wonder at the way primitive man arranged, in hewn stone such powerful symbolism."
Beside Maes Howe, the Ring of Brodgar is one of the finest stone circles anywhere, with 60 stones, of which only 27 remain standing now. The stones are set within a circular ditch up to three metres deep and nine metres wide that was carved out of solid bedrock. The Odin stone - which stood nearby - had a hole through which lovers clasped hands and swore everlasting love. The Oath of Odin meant the contract was binding forever. Unbelievably, a farmer in the 19th century destroyed this and toppled other stones until locals re-erected them a century ago.
Ten miles to the west, Skara Brae is unique. This well-preserved village lets you see how people lived when Maes Howe was built 5,000 years ago. Revealed after a severe storm in 1850, this prehistoric community was occupied for 600 years until it was inundated by water and sand in a Pompeii-like storm that killed many as they slept.
The whole area is covered with powerful, enduring symbols that outlived the culture that created them - and helped to create Scotland. Their secrets are locked up in stone and in the outlook of the visitor. Like life itself, the wonders of Orkney can be argued over endlessly, but never explained. They are perfect northern puzzles for questing Scots.