Sooner or later, every professional footballer must bring the curtain down on their playing days, in the process making way for the next generation of wunderkinds to emerge. As 2008 draws to a close, FIFA.Com looks back at the notable careers of some of the big names to depart the footballing stage over the last year.

Oliver Kahn, one of the greatest goalkeepers of recent times, played his final competitive game in May this year. The three-time FIFA World Goalkeeper of the Year (1999, 2001, 2002) can look back on a career littered with silverware after claiming 20 domestic titles just in his spells at Karlsruhe and Bayern Munich. Additionally, Kahn twice picked up winner's medals in European club competitions with Bayern after lifting the UEFA Champions League trophy in 2001 and the UEFA Cup in 1996. On the international scene, the custodian was capped 86 times and helped Germany take the UEFA European Championship in 1996. Though he never won a FIFA World Cup™ winners medal, ‘The Titan’ was awarded the adidas Golden Ball at Korea/Japan 2002, where the Mannschaft finished runners up to Brazil.

Kahn’s goalkeeping adversary from the 2001 Champions League Final, Santiago Canizares, also announced his retirement in the summer at the age of 39. It is unlikely the shot-stopper will have fond memories of that final, however, after losing to Kahn’s Bayern side in a penalty shoot-out - the second time in successive years that Valencia had to be content with runners-up spot in the showpiece event. Despite winning just about everything possible at club level during spells at Real Madrid and Valencia, the Spaniard only managed to pick up one title with the national side - a gold medal at the 1992 Olympics.

Someone with happier memories of Europe's premier club competition is former Brazilian striker Romario, who was the competition’s top scorer in 1990 and 1993. At the age of 42, Romario announced in April that he was finally hanging up his boots after a career lasting more than 20 years. The Brazilian would probably consider 1994 as his golden year when, in the space of 12 months, the prolific striker helped the Seleção win the FIFA World Cup in the USA (being voted Player of the Tournament in the process), picked up a Spanish league title with Barcelona and was voted FIFA World Player of the Year. The diminuitive front-man, who won a silver medal with the Auriverde at the Seoul Olympics, played for a total of eight different clubs in his lengthy career that included four different spells at Brazilian side Vasco de Gama. In recent years, Romario was an active beach soccer player even helping Brazil claim third place at the FIFA Beach Soccer World Cup in 1995.

Whether Serginho will follow in his compatriot’s footsteps by ‘taking to the sand’ on his retirement remains to be seen. The 37-year-old AC Milan midfielder bowed out of the game in May, ending a career that included a Champions League success with the Rossoneri in 2003 and a Copa America title with Brazil in 1999 (two years after Romario’s success with the Seleção in the same competition).

He may have less trophies than Serginho to show for all his endeavours, but Portugal's Rui Costa was an equally invaluable member of his national side. Along with Figo and Vitor Baia, Costa was part of Portugal’s much-lauded ‘golden generation’ who promised so much after winning the FIFA World Youth Championship in 1989 but never fully realized their potential on the international stage. In contrast, Costa’s haul of silverware at club level is enviable, with the midfielder collecting one Serie A title, one Italian Cup, one Italian Super Cup, one Champions League and one UEFA Super Cup during his five seasons with AC Milan.

Another Portugal star calling time on his career this year was striker Pauleta, who in his 88 games for the national side, managed to overtake Eusebio to become his country’s all-time leading goalscorer. Curiously, Pauleta is the only national team player never to have competed in Portugal’s Superliga after spending his entire career at clubs outside his home country (Deportivo La Coruna, Bordeaux, Paris St. Germain). After helping Deportivo claim a first Spanish league title in 2000, Pauleta went on to twice win the French Cup and finished as Ligue 1's top scorer on three separate occasions.

Another player who called time on a glittering career in 2008 was France’s Lilian Thuram. The central defender who enjoyed successful spells at Juventus and Barcelona played a record 142 times for the national side and helped L’Equipe claim the FIFA World Cup in 1998 and the European Championship two years later. Thuram’s compatriot Johan Micoud also decided to call it a day in the summer after being released by Bordeaux. Despite being feted as one of the most skilful players of his generation, the 35-year-old midfielder was mostly a peripheral figure for Les Bleus, with his favoured position being occupied by none other than Zinedine Zidane. Micoud, who also played at Cannes and Parma, spent four successful seasons at Werder Bremen between 2002 and 2006, helping the north German team to a league and cup double in 2004.

Claudio Reyna, the first American to be named in a FIFA World Cup All-Star team, also announced his retirement this year at the age of 35. The former Rangers, Sunderland and Manchester City player who was known affectionately in Britain and the States as 'Captain America' led the Stars and Stripes to the quarter-final of the Korea/Japan 2002, where they went out to eventual finalists Germany.

Another national team captain following Reyna into retirement was Chile’s Marcelo Salas. The former Lazio and Juventus star began his career at Universidad de Chile in 1994 before joining Argentina's River Plate, where he was named Latin American player of the year in 1997. During his time in Italy, the striker picked up the Scudetto three times (2000, 2002, 2003) before returning to South America for second spells at his first two clubs. El Matador, as he was known, became Chile’s all-time leading scorer, hitting 37 goals in 70 appearances for La Roja.

Other well-known names to bow out in 2008 included Frederic Dehu (France), Anti Niemi (Finland), Tony Vidmar (Australia), Teddy Sheringham, Andy Cole (both England), Hazem Emam, Nader El Sayed (both Egypt) and Jose Luis Sierra (Chile).

If you know of any other notable footballers who hung up his boots this year, then why not let us know.