Travel: Long Haul - Domeward bound journey around the world

From the Pantheon in Rome to a mega-stadium in Houston, Simon Calder celebrates some of the outstanding hemispheres of the globe

Demanding Dome: the dome of St Paul's Cathedral

The magazine of the Friends of St Paul's is called Dome. Wren's masterpiece needs all the friends it can get, given the developers' endeavours to conceal it behind barricades of nasty office blocks. The tide may be turning; there is talk of demolishing one or two of the more offensive encroachers, and when the Millennium Footbridge is opened from the Bankside Gallery, pedestrians should be able to approach Britain's biggest cathedral with proper reverence.

As a tourist treat, the Dome - which tops out 365ft above the scruffy City pavement - is good fun, if alarmingly expensive. You can send your sweet nothings whizzing around the Whispering Gallery, which rings the inner cupola, then venture up and out to the Golden Gallery at the top of the dome for a grand panorama of London. There is a grand total of 530 steps on the way up, and a mysterious 13 more on the way down.

St Paul's (0171-246 8348) opens to sightseers daily, except Sunday, from 8.30am. The steps to the galleries, however, do not open until 9.30 or 10am. Notices warn "Cathedral Cleared of Sightseeing Visitors 1630hrs". Admission to the cathedral and galleries is a spectacular pounds 7.50 for adults, pounds 3.50 for children

The Dome in Rome: the Pantheon

By its very name, the Pantheon celebrates the multiplicity of gods that prevailed in ancient Rome. That this amazing holy hemisphere has remained standing for the best part of two millennia is as much a tribute to ecclesiastical alacrity (in 609, the Pantheon was renamed: not as the Monotheon, but as the church of Santa Maria ad Martyres) as it is to the genius of those engineers who built it for the emperor Hadrian around AD120.

They constructed what is still the largest stone vault ever built, beating even the dome of St Peter's across the Tiber. The hole that occupies the middle 30ft of the 150ft diameter is not an architectural admission of defeat, but a deliberate emulation of the smoke flue of round-roofed Etruscan dwellings - on which the Pantheon is loosely based.

A Stable Environment: the Dome, Brighton

The Sussex resort wins first prize in both "best use of a former stables" and "how best to fill a dome" competitions. The Royal Pavilion, which the Dome nudges, was built before the Brighton Belle began transporting royalty by rail. The considerable quota of horses needed for transportation to and from the capital implied a mighty stables.

The necessary quarters were constructed slightly downwind of the prevailing sea breezes that wafted over the ersatz oriental pavilion. When the train arrived midway through the 19th century, the horses bolted, leaving a building in some dereliction - a fate parallelling the rather battered pavilion. But its potential as an auditorium was realised, and hands became something that applauded everyone from Neil Sedaka to Eric Clapton.

Dome of the Oilers: the Houston Astrodome

This mega-stadium, alongside the Interstate highway I-610 that elbows its ungainly way through the Texas city, is more than just a sports arena. It is also the domain, if that is the appropriate term, of Astroturf, as befits Astrocity, USA. The football team, the Oilers, share the venue with the city's baseball team, known (inevitably) as the Astros. With a capacity of 76,000, it is one of the world's largest enclosed stadiums. There are daily guided tours that feature a dazzling display on the giant scoreboard, or you could put the cash towards a cheap ticket for a baseball or football game instead.

Home of the Dome? The Telescope Dome, Old Royal Observatory, Greenwich

The Millennium Dome, though technically within the confines of the Borough of Greenwich, is but a distant relation to the real thing. The name Greenwich comes from the old Saxon term Grenavic, meaning "green hamlet". So it was when Charles Dickens set the wedding breakfast for Our Mutual Friend at the Trafalgar Tavern, and when the 1881 convention in Washington established the Heseltine-Mandelson axis - sorry, Prime Meridian - as passing through the then Royal Observatory. (It has since moved via Herstmonceux in East Sussex to Cambridge.)

Today, the Observatory is a museum devoted to space and time, with the old 28-inch telescope still housed within its handsome hemisphere.

The Old Royal Observatory (0181-858 4422) is open from 10am-5pm daily. Admission of pounds 5 (pounds 2.50 for children) includes entry to the nearby National Maritime Museum and the Queen's House

The Dome for Ewe: Rotorua Agrodome Leisure Park, New Zealand

New Zealand's agricultural heritage is, if you will forgive the phrase, rammed home at this ovine celebration. The North Island's top tourist town includes this venue for demonstrations of shearing techniques and sheepdog displays, as well as all you ever wanted to know about sheep farming. You learn, for example, that because of the enormous size and ruggedness of its farms, New Zealand has bred a special tough dog called a huntaway whose loud bark shoos the sheep away.

The "agricultural stage shows" at the Agrodome (on the west side of Rotorua Lake) take place several times daily