There is a bridge over the Bosphorus Strait which links not only two sectors of the city of Istanbul but also joins the two continents of Europe and Asia. Now, there may have been a lot of talk about bridges lately but THAT'S what I call a bridge.
Istanbul, the only city in the world to straddle two continents, is nevertheless distinctly Asian. Mosques with tall minarets are silhouetted against the sky and when the calls to prayer echo all around the city the atmosphere is unmistakably exotic and intriguingly foreign.
The sheer abundance of historical palaces and treasures conveys a sense of the overwhelming opulence of the sultans of the past. In fact, so much has been preserved that the visitor is in danger of sightseeing overload.
The city is teeming with 12 million people and traffic is dense and noisy along modern thoroughfares, hooters sounding impatiently all the time.
The hotels, banks, offices and restaurants are in the European sector. Nestling among them are narrow streets with washing lines strung across.
The Asian side is mainly residential and here is evidence of poorer living conditions alongside the mansions nearer the shore.
At weekends, families, with the women dressed in the head scarves and long dresses of the Muslim tradition, go to a high point on the hills with views all over Istanbul - if the smog hasn't descended to obscure the panorama. The Turks need Mary Harney to sort that problem out.
Unique silhouette
Perhaps the most famous image of Istanbul is of the Blue Mosque with its six minarets forming a unique silhouette against the skyscape. Inside, the reason for its popular name becomes apparent as more than 20,000 blue tiles and mosaics line the huge interior.
Bigger than any cathedral, it has a strangely calm and quiet atmosphere in spite of the busloads of tourists from all over the world who pad in carrying their shoes in specially provided green plastic bags.
Just across from the mosque is the vast Hagia Sofia, considered one of the eight wonders of the world. It is one of Istanbul's oldest buildings, having been completed in 537. It has been a mosque and a Christian church at various times but is now designated as a museum.
The best known of the palaces is Topkapi, a sultan's palace dating from 1470 which overlooks the river. Ideally, the visitor would need about two days to get around it as there are so many separate buildings, including the harem section which, interestingly, seemed to hold a particular fascination for male tourists - does the new man harbour old fantasies? They weren't so keen on the circumcision suites, though.
The treasury is breathtaking in its abundance. Cabinets are full of items, such as boxes, swords, even thrones, all encrusted with rubies, diamonds, sapphires, turquoise, and emeralds so big that it is hard to take in that they can be real at all.
Priceless emerald
The priceless square emerald at the top of the Topkapi dagger, displayed singly in a specially-lit cabinet, is so big it would cover the palm of a hand. In another cabinet, resting on black velvet and made to move slowly so that its many facets can catch the light is the breathtaking Spoonseller's Diamond, also known as the Pigot Diamond, the size of an apple.
The palace is full of surprises. Going into yet another museum, I was astonished to find the glass cases actually held relics of the Prophet Mohammed and, as such, the building is a holy shrine for Muslims, with prayer chants ringing through the rooms.
And one of the cases in the treasury rooms provides another unexpected discovery. It displays what is said to be the hand of John the Baptist, most of which is encased in pure gold.
A silver collection, with huge samovars, and the pottery and porcelain section, which includes hand-painted bowls like satellite dishes, add to the seemingly endless abundance.
Along the outer walls of the palace runs the railway where, in more elegant times, the Orient Express completed its journey. Behind is the now rather run-down hotel where once the rich and famous like Agatha Christie stayed.
Shopaholics will overdose in Istanbul because the covered bazaar has more than 3,000 shops in a maze of 60 streets. One courier said when he first visited the Grand Bazaar as a student at the university nearby, he got lost and couldn't find his way out for three hours.
Turkish carpets
Shop after shop contains everything from Turkish carpets to Aladdin-style slippers, to fezes, coffee sets, jewellery, even belly-dancers' outfits (no, I did not buy one). I don't know which would take longer - attempting to sort out the rubbish from the quality goods or trying to remember in which shop in which street you saw something you liked.
Restaurants abound in the European sector and, as in every other city, vary. But Turkish food can be excellent, with delicious vegetables and salads. Lamb seems to be the main dish. There are also good wines, for example, one called Yakut, a light and fruity red.
Like all cities, there is good and bad. Tourists are warned about the sellers around the sights and are told to be wary of them. And I even witnessed a bit of soccer hooliganism, with young Turks squaring up to police and taunting them outside the main football stadium before a match.
But the city's charms far outweigh any drawbacks. In fact, it has everything - even the ubiquitous Irish pub. This one is called The James Joyce which, needless to say, is not included on my extensive list of sights to visit when one day, hopefully, I return to this most fascinating and absorbing of cities.