Almost as soon as the fighting was over, many of the battlefields started attracting visitors. Wives, parents, sisters and brothers went to find graves, seek information about missing relatives or simply to pay their respects. The highest concentration of visitors was to the Western Front, which stretched from the North Sea to the Alps; other fronts - such as the Mesopotamian and Palestinian - were way beyond the resources of those who had lost loved ones. Many visitors went to Flanders in western Belgium, where hundreds of thousands of soldiers died.
Today, most travellers to the killing fields of Flanders arrive via one of the short sea crossings. The main approaches are on Eurotunnel (08705 353535; www.eurotunnel.com) from Folkestone to Calais; P&O (08706 009 009; www.poferries.com) and SeaFrance (08705 711 711; www.seafrance.com) from Dover to Calais. As early as 1919, Michelin published a guide to the battlefields of Flanders, the ground still shell-torn and dotted with abandoned military vehicles. Today, you can buy a range of guides and maps, including The Footsteps Map of the Western Front (£10.95). The landscapes where conflict took place may look less shockingly scarred, but the poignant pilgrimages to the memorials and sites of fighting continue.
The Flemish town of Ieper, known as Ypres in French, and Wipers by British troops who fought there. It receives more than 200,000 visitors every year. In December 1915, publication in Punch of the poem "In Flanders Fields" by Canadian medical officer John McCrae caused a significant stir. Commemorating the deaths of thousands of young soldiers in the Flanders trench warfare, it gave rise to great waves of patriotic feeling. McCrae's allusions to poppies were later the inspiration for the emblem of remembrance. McCrae served in the trenches near Ieper, tending the wounded and dying and attempting to counteract the debilitating effects of chlorine gas used against Allied troops in the "Second Battle of Ypres" in April 1915. The medieval Flemish cloth town came under almost constant bombardment during the First World War, and most of it was reduced to rubble. Subsequently it was painstakingly rebuilt in Flemish brick-style. Since 1998, its Cloth Market at Grote Markt 34 has housed the In Flanders Field Museum (00 32 57 239 220; www.inflandersfields.be; October-March open 10am-5pm daily except Monday; April-September 10am-6pm daily; adults €7.50/£5.35) telling the story of the town's wartime horrors and bravery. Guided tours of the outlying battlefields can be booked through the Ieper Tourist Office (00 32 57 239 220; www.ieper.be), in the Cloth Market.
A few specialist travel companies offer dedicated tours of battlefields with departures from the UK. Among them, Holts Tours (0845 375 0400; www.holts.co.uk) has a four-day introductory trip to the major British battle sites of the Western Front entitled "It's A Long Way to Tipperary". The price of this trip, from £445 per person, includes coach transport from London, half-board accommodation, expert guidance and entrance fees.
In addition, Holts is arranging a four-day trip to Ieper in August next year to commemorate the 90th anniversary of the Third Battle of Ypres. Also known as the Battle of Passchendaele after a nearby village of the same name, this British offensive started boldly at the end of July 1917 and ended after much bloodshed in November. The anniversary trip costs £475 per person.
This year has seen commemorations for the 90th anniversary of the Battle of the Somme in Picardy. It was one of the longest and most devastating battles of the war, with more than a million casualties from both sides.
By mid-1916 the British and French Allies on the Western Front had been locked in a stalemate of trench warfare with the Germans for about 18 months. On 1 July that year they launched a joint* *offensive that was intended to result in a decisive victory. Fighting finally stopped on 18 November 1916. The battle weakened the German army but failed in the original goal of bringing an early end to the war. Today there are some 250 cemeteries in the Somme area as well as sites where trenches have been preserved. You can make a 40-mile Circuit of Remembrance between the towns of Peronne and Albert (www.somme-battlefields.co.uk). Or you can book a guided tour through the Albert Tourist Office at 9 Rue Gambetta (00 33 3 22 75 16 42; www.tourisme-albert.net). Companies arranging Somme trips from the UK include Somme Battlefield Tours (01202 880211; www.battlefield-tours.com). The Imperial War Museum has an online exhibition on the Battle of the Somme: www.iwm.org.uk.
This year Verdun in the Lorraine region of eastern France has been marking another 90th anniversary. From February to December 1916 the Battle of Verdun took place between French and German troops, resulting in about half-a-million French casualties and more than 400,000 German losses. Guided tours of the battlefields and memorials are organised through the Verdun Tourist Office at Place de La Nation (00 33 3 29 84 18 85; www.verdun-tourisme.com). Further north, in the Pas-de-Calais area, are two striking monuments. Beyond Arras near the village of Ablain-Saint-Nazaire, the hilltop oratory of Notre Dame de Lorette became the focus of a year-long battle between German and French troops from October 1914. It was subsequently transformed into a major French memorial with a vast cemetery and ossuary. Nearby, about 10km north of Arras, is a monument to the Canadian troops who fought for Vimy Ridge in April 1917. It sits in the heart of a park where the wartime trenches have been restored as a memorial.
Leger Holidays (0845 458 5599; www.legerbreaks.info), which runs a range of First and Second World War trips from the UK, plans a special, 90th-anniversary trip to Vimy Ridge next April. As well as the Canadian memorial, the three-night tour takes in Arras, Notre Dame de Lorette and the grave of British war poet Edward Thomas at Agny. The trip costs £229 per person.
AND THE ITALIAN FRONT?
In May 1915, Italy declared war on the Central Powers. Its army crossed the Julian Alps into Slovenia's Soca Valley, until then under Austro-Hungarian rule. Trench warfare between Italian and Austrian troops continued around that area until October 1917 when a combined German and Austrian offensive sent the Italians into chaotic retreat. The Italians lost more than 500,000 troops; a further 250,000 were taken prisoner. Ernest Hemingway's A Farewell to Arms, based on the author's experiences as an ambulance driver with the Italian army, vividly captures what life was like on the Soca front and in flight.
Hemingway was based mainly at Kobarid (known as Caporetto by the Italians) and today the small town is dominated by an enormous war memorial and ossuary that contains the remains of more than 7,000 Italian soldiers. There is an impressive war museum here (00 386 5 389 0000; www.kobariski-muzej.si; open daily 9am-6pm; admission 950SIT/£2.70) where you can pick up a leaflet for a historic walking trail that will take you to trenches and gun emplacements dug into the town's surrounding slopes. As if in defiance of the fighting, the surrounding scenery of woods and mountains is staggeringly lovely, while the turquoise ribbon of the river Soca is breathtaking.
The main gateway to the region is Trieste in Italy, served from Stansted by Ryanair (0871 246 0000; www.ryanair.com), though the Slovenian capital, Ljubljana, is also an option; it is served from Stansted by easyJet (0905 821 0905; www.easyJet.com), from Gatwick by Adria (020-7734 4630; www.adria-airways.com) and from Luton by Wizz Air (00 48 22 351 9499; www.wizzair.com).
HOW ABOUT GALLIPOLI?
Site of the ill-fated Allied landings of 1915, the Gelibolu peninsula on Turkey's Sea of Marmara is now a lovely, green stretch of land with some fine beaches - as well as memorials and cemeteries. The Allied assault on the Turkish forts of the Dardanelles Straits started in February 1915 and ended in defeat around Christmas that year. The human cost amounted to 52,000 Allied deaths and Turkish losses of anywhere between 50,000 and 200,000 men.
The easiest access to the area is from Istanbul's Ataturk airport, served from Heathrow by British Airways (0870 850 9 850; www.ba.com) and Turkish Airlines (020-7766 9300; www.thy.com) - which also flies from Manchester. To stay in the Gallipoli area, the nearest centres with hotels and restaurants are at Eceabat on the eastern side of the peninsula or the town of Cannakkale just across the Dardanelles Straits. It is also possible to make day tours from Istanbul: Plantours, for example (at Cumhuriyet Cadessi 131/1, 343 Elmadag, Istanbul; 00 90 212 234 7777; www.plantours.com) offers private day trips from the city taking in the ancient site of Troy as well as the battlefields for US$440 (£244) for two people. From the UK, nine-day tours are offered by the War Research Society (0121 430 5348; www.battlefieldtours.co.uk).
WHERE CAN I LEARN MORE IN BRITAIN?
Head for the Imperial War Museum (020-7416 5320; www.iwm.org.uk) on Lambeth Road, London SE1. Among the permanent collection here is the absorbing First World War Gallery where you can explore the causes of the war and get an insight into life in the trenches. Remembrance events this weekend include a Peace Lecture tomorrow at 2pm (free) by Baroness Shirley Williams, former MP and daughter of the nurse, pacifist and writer Vera Brittain. The museum opens 10am-6pm daily, admission free except for some exhibitions.
In Manchester, the Imperial War Museum North at Trafford Wharf (0161 836 4000) houses the gun that fired the British Army's first shell of the war. The fateful shot from the 13-pounder field gun was fired on 22 August 1914 near Binche in Belgium during the retreat from Mons. The museum opens 10am-5pm daily, admission free. A new addition to the permanent displays in the Silos galleries is the story of Edith Cavell, the Red Cross British nurse who served in Belgium and was executed at dawn on 12 October 1915 for assisting Allied prisoners in escaping to neutral Holland. Edith Cavell is buried close to the south door of Norwich Cathedral, beneath a sprawling cedar. "To the pure and holy memory of Edith Cavell", reads the headstone, "Who gave her life for England". Her memorable last words are on display: "Patriotism is not enough. I must have no hatred or bitterness towards anyone."
WHERE DID THE MAJOR CONFLICTS TAKE PLACE?
The principal sea battles of the First World War included confrontations near the German naval base of Heligoland (1914), near Jutland (1916), and in the Otranto Straits (1917), which connect the Adriatic and Ionian Seas.
On land, the conflict was essentially played out on seven "fronts" - some of the battle sites now very accessible, others distinctly war-torn by more recent aggression. British and Indian troops battled against the Turkish army on the Mesopotamian Front, which lies in today's Iraq, where the conflict essentially started with the capture of Basra by the Allies in November 1914.
On the Palestinian Front, British and Turkish troops clashed three times at Gaza before Jerusalem fell to the Allies in December 1917. In 1915 Turkey's Gelibolu, or Gallipoli, peninsula saw horrific losses for British, French and particularly ANZAC (Australia-New Zealand Army Corps) troops. Over in the borderlands of today's Italy and Slovenia, the Italians battled against Austro-Hungarian and then German troops. On the Eastern Front, the Tsar's Imperialist forces confronted Germany and Austria on Russia's western borders, with grim results.
The Western Front effectively referred to a narrow zone in the border area of Belgium and France where trench warfare between the Allies and the Germans took place more or less from Switzerland to the North Sea. From the UK, today the most visited battle sites are along the Western Front, in particular the Somme in Picardy, northern France, and Ieper in Belgium.
A comprehensive account of the war is given on the website www.firstworldwar.com.