"You've got to see the amazing Blue Tiles in Molonglo Gorge," boasted the barman, a self-confessed staunch supporter of Canberra and who also claimed to be an avid bushwalker, hailing it as "a spectacular site", or words to that effect... 27 years is a long time ago.

"When the sun hits a pool of water on a certain angle it looks like the surface is covered in a layer of sparkling cobalt-coloured tiles," regaled the barman who was trying to convince his audience of thirsty first-year university students that Canberra was worth exploring by day as well as by night.

Ever since that Canberra Day, witnessing this optical illusion has been on my bucket list.

You'd think being such an easily accessible recreation area I'd have checked it out by now, however, every time I've planned to hike up the 6.5km (return) walking track to the Blue Tiles, I've had to postpone. Once it was due to extreme bushfire risk (the gorge is no place to be caught in an inferno), on another occasion due to rising river levels, and a number of times due to cloudy skies (apparently, the bluer the sky the better the spectacle).

So, with last weekend's showers reducing the fire risk, earlier this week under mostly sunny skies I finally set off to view the fabled Blue Tiles in all its glory.

I arrive late morning to a deserted carpark off Sutton Road between Canberra and Queanbeyan. The vandalised sign at the trailhead which outlines the walking route along the northern side of the gorge to Blue Tiles also tells of the area's remarkable geology.

"The gorge formed over 15 million years ago when two faults, Lake George and Queanbeyan lifted a section of land across the path of the Molonglo River. Rather than being blocked by this barrier, the gorge formed as the river cut through the rising land".

At first the track is well-worn, no doubt from thousands of curious day trippers taking a short stroll upstream while their mates turn snags on the BBQs at the main picnic area, location adjacent to the car park. But it's not long before the track steepens, and handrails provide much needed support to clamber up, via a series of switchbacks, higher and higher.

After the first few climbs, the track, like me, starts to look a little tired. At ad hoc intervals rickety old wooden posts with faded numbers line, which I later discover are the remnants of a time-trail developed by ACT Forests in conjunction with government geologists last century, line the side of the track.

Before long I'm atop the northern escarpment peering down into deep recesses of the gorge. From this height the river is a mix of reeds, and layers of sandstone which dam the water, creating a number of pools in which the blue sky punctuated by fluffy white clouds is perfectly reflected. Wow, if the still water looks that impressive here, I can't wait to see the Blue Tiles.

As the crow flies, Molonglo Gorge is only about ten kilometres from Parliament House, but I may as well be in the boondocks of Kakadu's backcountry for there's not another human within cooee, meaning a number of shingleback lizards enticed onto the path by the warm autumn sun is my only company.

A rumbling noise booming up the gorge suddenly interrupts my tip toeing through sunbaking reptiles. It can't be a southerly buster, can it? It certainly wasn't forecast, besides the trees aren't moving.

As the roar gets closer and closer it starts to sound like a train.

And there's a good reason for that – it turns out to be the 11:53am Southern Xplorer on its way to Sydney. Immersed in the tranquillity of the gorge I'd completely forgotten that the Canberra to Goulburn line runs along the southern side of the gorge, disappearing twice into tunnels.

I whip out my camera and through the thick undergrowth partly obstructing my view attempt to zoom in on the silver carriages before they disappear into the first tunnel.

While trying to hurriedly focus through the viewfinder, I foolishly forget I'm on the edge of a precipice and lose my footing.

I reach out with my spare hand and grab a tree branch. Phew! It's just in the nick of time, but I've missed the shot of the train.

On the plus side, at least I didn't stumble while navigating along the far-side of the gorge, which at this point, half-way to Blue Tiles is a near vertical scree slope. How the occasional black cypress pine precariously clings to these cliffs is a marvel of nature. Little wonder under these unfavourable conditions botanists report the shapely trees grow less than 10 centimetres per year.

Further up the gorge piles of hundreds logs washed downstream from the floods of a few years back harbour the odd snake or two. Bleached white from the sun from this height they resemble giant matchsticks.

Thankfully for my ticker the track evens out for the last kilometre to Blue Tiles and as I round the last bend in the river, I clutch my camera, ready to capture the much anticipated phenomena. The sun is shining and the river is still, which according to the clued-up barman, were "the two essential ingredients to view the optical illusion".

However, on arrival, I couldn't be more disappointed. Sure, there's a deep pool of water but there's no blue reflection. And definitely no tiled effect.

Rather than wallow in discontent at the picnic area which is currently strewn with weeds anyway, I retrace my steps for about two minutes, plonk myself onto a log overlooking the river. Between bites of my sandwich, I double check my location on both my map and GPS. There's no mistake, I'm without doubt at Blue Tiles. Geez, what a let-down.

On the trek back, the sky clouds over, and a couple of times the increasing easterly appears to 'sing' through the railway tunnels. It's a haunting sound, a bit like a blowhole in action, only higher pitched. Maybe I'm dreaming it, or maybe I've got singing on the mind after searching in vain for the melodic stones of the south coast last week (Singing Stones, March 4)? Tunnels can't sing, can they?

Back at the car, I contact ACT Parks and Conservation to double check on the origins of Blue Tiles. According to the local ranger, "It's so-named as a heap of blue bathroom tiles were once found there."

Oh dear, it's got nothing to do with the area's extraordinary geology after all and the blue tiles have long since been cleaned up by the rangers. I've been had.

I don't have the heart to ask them about the singing tunnel.

Despite my obvious let-down, the gorge walk is still rewarding, and one during which I've learnt two important lessons.

Firstly, don't be too distracted by taking photos while standing on the edge of a cliff, and secondly, always take what a barman tells you with a grain of salt, especially if it's the Canberra Day weekend.

Molonglo Gorge Walking Track: Allow 2.5 hours (return) for this 6.5km (return) moderately graded hike from the track-head off Sutton Road near Queanbeyan to Blue Tiles picnic area.

Did You Know: Mountain galaxias, a small native fish have been spotted in pools in the gorge where they are protected from introduced predators such as redfin which are unable to negotiate the rapids which lead into the gorge.

Train times: For added excitement, time your walk when the train to and from Sydney is scheduled to chug through the gorge.

Singing tunnels: Have you ever heard the tunnels in the Molonglo Gorge "sing"? Or any other tunnel for that matter? If so, I'd love to hear from you.

A number of readers including Richard Fisher, of Mossy Point, have attempted to solve the case of the curious cork embossed with "Canberra" that was salvaged from the bottle of champagne smashed over the bow of the MV Dolphin, when it was launched at Huskisson in 1936 (Champagne Mystery, 31 December)

"It's almost certain that HMAS Canberra's commissioning in July 1928 would have attracted a "commemorative" labelling of the champers for the celebrations," says Fisher, speculating "perhaps a leftover, or a souvenir, was used to launch the MV Dolphin?"

While intelligence on what wine, if any, was produced when HMAS Canberra was "commissioned" in Clydebank on July 9, 1928, is scant, initial investigations by this column indicate that Her Royal Highness Princess Mary used "a bottle of Australian red" to break over the bow of the HMAS Canberra when it was 'launched' a year earlier in Glasgow.

This is a fact that Graham Hinton, curator at the Jervis Bay Maritime Museum, which holds the cork as part of its collection, says rules out any theory the mystery cork originates from the launch of the HMAS Canberra.

"The 'Canberra' cork salvaged from the launch of the MV Dolphin had to be from a bottle of sparkling wine because of the way it was wired onto the neck of the bottle," explains Hinton.

As many of us raise a glass to our fair city this Canberra Day weekend, perhaps some Navy historians can shed some light on this cork conundrum?

Clue: Walter planned this.

Degree of difficulty: Medium

Last week: Congratulations to Judy Stevenson, of Macarthur, who was first to correctly identify last week's photo, as Walk in the Park, one of several eye-catching artistic creations in Natalie Maras' Far Flung Universe exhibition which is on show at the Australian National Botanic Gardens until March 12. "The beautiful artwork represents a paper daisy surrounded by lichen," reports Stevenson who just beat Julie Ryder, of Weetangera, and Kristen Robinson, of Belconnen, to the coveted weekly prize.

How to enter: Email your guess along with your name and address to timtheyowieman@bigpond.com. The first email sent after 10am, Saturday, March 11, 2017 with the correct answer wins a double pass to Dendy cinemas.

CONTACT TIM: Email: timtheyowieman@bigpond.com or Twitter: @TimYowie or write c/- The Canberra Times, 9 Pirie Street, Fyshwick. You can see a selection of past columns online.