Football history is littered with clubs who once ruled their domestic landscapes or even conquered Europe, only to fall away from the top flight in the years that followed. While the likes of Leeds United, Nottingham Forest, Schalke and Deportivo have recently clawed their way back to prominence, a host of storied sides remain stuck below the elite, waiting for their moment to return.
A ranking of Europe's current "sleeping giants" requires a mix of criteria: history, heritage, fanbase size and stadium capacity, among clubs that retain genuine potential despite being outside their top division. Recent success rules a club out of contention, which is why clubs such as West Ham, Wolves, Stade de Reims and Nantes do not qualify, while financially collapsed sides like Boavista and politically complicated cases such as Steaua Bucharest are also excluded.
At the lower end of such a list sits Bursaspor, Turkish champions in 2010 who broke Istanbul's stranglehold on the title before sinking as low as the fourth tier in 2024. The Bursa club, who play in a distinctive crocodile-shaped 43,000-seat stadium, are working their way back up.
Germany provides several entries, starting with Dynamo Dresden, eight-time East German champions who reached a European Cup semi-final in the 1970s before financial trouble sent them tumbling down the leagues after reunification. They now draw strong crowds in 2.Bundesliga. Kaiserslautern, the only club to win the Bundesliga immediately after promotion, continue to average crowds above 46,000 despite years away from the top flight, and even reached the 2024 German Cup final before losing to Bayer Leverkusen. Hertha BSC, with pre-Bundesliga titles and a memorable 1999 Champions League win over Chelsea, currently top the second division and regularly fill Berlin's Olympiastadion, with talk of a new stadium on the Olympic Park site.
In England, Sheffield Wednesday represent a classic case of dormant potential. Four league titles - the last nearly a century ago - and a League Cup triumph in 1991 give the Owls a rich heritage, but administration and relegation last season left them in League One before a US consortium took over the club in May.
France offers two strong candidates. Bordeaux, champions as recently as 2008-09, suffered a dramatic collapse through administration and financial turmoil, dropping to the sixth tier before being purchased by US investment fund Park Bench for a symbolic one euro. Saint-Etienne, historically France's most decorated club before Paris St-Germain surpassed them, reached the 1976 European Cup final and continue to produce elite talent, including William Saliba and Wesley Fofana, despite spending four of the last five seasons outside Ligue 1. They narrowly missed returning this year, losing a promotion play-off to Nice.
Real Zaragoza, famous for Nayim's extra-time winner against Arsenal in the 1995 Cup Winners' Cup final, now play in Spain's third tier while developing a new stadium for the 2030 World Cup. Club legend Ander Herrera, who returned to his boyhood side at 37, insists the ambition remains intact. "Real Zaragoza belong to Europe, they belong to compete for trophies, to be fighting with the biggest clubs in Spain and in Europe," he said.
Topping the list is Sampdoria, who enjoyed a golden era under Paolo Mantovani's ownership, winning the 1990-91 Serie A title, lifting the Cup Winners' Cup in 1990 and reaching another European final in 1992 with stars like Gianluca Vialli and Roberto Mancini. After financial turmoil nearly sent them into Serie C, Sampdoria are now under new ownership, with their shared Stadio Luigi Ferraris set for renovation ahead of Euro 2032.
Whether any of these clubs can fully awaken their former glory remains uncertain, but each retains the infrastructure, support and history to suggest a return to the top is far from impossible.
Based on reporting from BBC Sport.