Patrick Geddes, one of the 20th century's greatest town planners, always maintained that the only way to get a sense of a city and the network of relationships between its buildings and spaces is to rise above the rooftops - which is why he proposed the Outlook Tower in Edinburgh.
Dublin now has its own version of the Outlook Tower, soaring high above Smithfield. What it offers is an extraordinary 360 degree panorama of the city, stretching out in the far distance to Dublin Bay, topped and tailed by Howth and Killiney. Nobody before has ever seen Dublin like this.
Nelson Pillar, blown up in 1966, rose 136 ft high from the middle of O'Connell Street; those of us who are old enough to remember walking up its endless stone steps will also recall how breathtaking it was to look out through the wire-mesh surrounding its open-air platform over the roofs of the GPO.
The new Observation Tower in Smithfield, which has yet to acquire a nickname, is a more than adequate replacement for the Pillar, albeit much further to the west. It is also higher, with a two-level glazed pod anchored atop the old Jameson Distillery chimney, which stood 170 ft tall without its recent addition.
A U-shaped glass and stainless steel external lift whisks visitors up to the pod at a metre per second; the more energetic can walk up a spiral steel staircase inside the 1895 chimney, the walls of which are five ft thick. The capacity of the lift is 21 people at a push, while 25 would fit comfortably on each level of the pod.
What awaits them is an extraordinary unobstructed view over Dublin, much more impressive than anything available from any high-level corporate boardroom. Its only rival is the observation deck just under the roof of Liberty Hall, but that's been closed to the public since a bomb exploded outside the building in 1972.
The view from Smithfield Village's new icon is of a quite chaotic city, a bit of a mess, really. "But it's a wonderful mess," says Terry Devey, developer of the old distillery site. Of course, there are all the domes and spires, but what about lumps like the car-park stacked on the roof of the Jervis Centre or the IMAX "black box" cinema on Parnell Street?
Southwards are the Four Courts, St Patrick's Cathedral and the unmistakable dome of Rathmines Church. To the north, you can see the Ballymun towers - all scheduled for demolition - Phibsboro Church, St George's, the entire mid-19th century facade of the Mater Hospital, as well as Broadstone and what's left of Grangegorman.
The Wellington monument dominates views to the west, which also includes the Guinness brewery, and its marvellous Market Street Storehouse, the former Dr Steevens' Hospital, Heuston Station, the Royal Hospital in Kilmainham, James Gandon's Army Headquarters and the distinctive red roofs of McKee Barracks.
Closer in, what's striking is an amazing regularity of the roofscapes of Oxmantown and the astonishing amount of development that has taken place in the wider area around Smithfield; new blocks of flats are visible in almost every direction, including the large scheme by Zoe Developments in the former Richmond Hospital.
Until Terry Devey arrived on the scene in 1996, Smithfield had been ignored by developers for a century. People in Dublin had lost their "mental map" of where it was or what it even looked like. And yet it is the city's largest civic space, with dimensions equivalent to two-and-a-half GAA pitches, according to Dublin Corporation.
It may not look like the Piazza Navona in Rome, but that's about the size of it. And the corporation, with EU help, is investing £3.5 million to remake the central space, following a design competition two years ago. The winners were architects McGarry Ni Eanaigh, who also designed a boardwalk for the Liffey quays.
The most extraordinary feature of their superbly realised scheme is the row of 12 beacons, each 85 feet high, with their wings spread as if ready to take off. When the gas braziers on top of these lighting masts were lit at the official opening last December, it was reminiscent of the liner scene in Fellini's Amarcord and almost as surreal.
The Observation Tower offers a clear overview of the diagonally-cobbled surface of Smithfield, neatly divided by granite pathways running in parallel. Indeed, it is only from this height that you can appreciate the subtlety of the design, which includes a gentle curve beneath the new streetlamps on the eastern side.
Inevitably, there is a grandstand view of Duffy's scrapyard - now the subject of major redevelopment proposals, including a slender 23-storey apartment tower - and of the geometric pattern of Smithfield Village, as laid out by its architects, A+D Wejchert. Beyond it, to the south, veteran developer John Byrne is building another new office block, alongside the planned LUAS line from Tallaght.
A+D Wejchert also designed the glazed observation pod, which was prefabricated in the Netherlands by a company specialising in airport control towers, assembled at ground level and then craned into position. It was meant to minimise visual impact on the chimney while also introducing an element of contemporary tension.
In 1996, when the Devey Property Group announced its plans for Smithfield Village, the observation pod seemed like an optional extra that might never be built. But Mr Devey was convinced that it would be an icon, complementing Chief O'Neill's Hotel, the Ceol traditional music centre and the Jameson Visitor Centre.
"I don't honestly know how much it cost, and don't want to know," he says. "But it's done and it's here, that's the main thing." And because it was driven by instinct rather than profit, he can can only hazard a guess that it might attract 150,000 visitors a year - plus corporate entertainment business, particularly in the evenings.
With the Great Book of Ireland also due to go on show here, as well as the shops and restaurants on glazed-over Duck Lane, the Observation Tower and all the rest of it, Mr Devey hopes to turn Smithfield Village into a "destination" - a goal that will receive a major boost from such events as the U2 "coronation" in the square this weekend.
The immense scale of Smithfield's civic piazza was lost when the corporation's parks department carved it up to plant trees in the middle of what then was a huge surface car-park.
The repaving of Smithfield is not yet complete; because of LUAS and other developments, the southern end has been left for phase two. The concrete control building, where the stage for U2 has been erected, is also unfinished. But these are minor irritants when set against the scale of what has been achieved so far.
It is hard to tell what impact the Fusano scheme, on the old Duffy's scrapyard, will have on the view towards the old Bluecoat School in Blackhall Place, lopsidedly framed by two different eras and types of corporation housing. One sure thing, however, is that there would be a great view from Smithfield's tower of the planned Millennium "spike" on the site of Nelson Pillar.
