What is the Sweet Track? Well, it's an ancient timber causeway which was built in 3806 or 3807 BC, when the Somerset Levels looked like this every winter, rather than fields bordered by rhynes.
Consisting of oak planks laid end to end on crossed wooden poles driven into the waterlogged peat, it linked the settlement of Westhay, then an island, with Shapwick, situated on a ridge of high land close to the River Brue.
This is a stretch of replica track ...
... and this is me walking along it, trying to balance by clutching at reeds. 'Deb doing neolithic walking,' Rachael observed. 'More like Bridge on the River Kwai,' reckoned the Northerner when he saw the photo.
It's believed that the track was only used for about 10 years before it was abandoned, probably due to rising water levels. It was uncovered around 5766 years later, in 1970, during peat excavations led by a man named Ray Sweet. The acidic and anaerobic conditions in the bog had prevented the wood from rotting.
We followed the approximate route of the original track through the woods. Although the land on both sides was swampy, the path itself was dry, being built of wood and chippings. It was cool beneath the trees on what was a hot and humid day.
Rachael says we stayed in the hide for an hour, watching birds and contemplating the weight of history in this tranquil spot. Perhaps unsurprisingly, it didn't seem that long.
She also says these mesmerising birds shadowing each other are marsh harriers, and I bow to her identification skills.
We walked back to the car around the lake, passing this magnificent oak in its absolute prime. I was making a mental note to come back on a frosty winter's aternoon to watch the starling murmurations.
Back at Rachael's home in Glastonbury, there was time for tea in her back garden with its wonderful view over to Wells and the Mendip Hills before I thrashed my way along the causeways to Watchfield, dashing into Rich's Cider five minutes before it closed to get a few litres of scrumpy. The perfect end to an excellent jaunt.