#2 Real Madrid (Spain)
Real Madrid were named the club of the 20th century by FIFA in the year 2000 and they have gone some way to retaining that title in the 21st century.
The century was begun in excellent circumstances as they defeated Valencia in Saint-Denis, France to win their eighth Champions League title and although their domestic form was not great, they again won the Champions League two years later in 2002 in what was their centenary year.
This period was marked by heavy spending by club president Florentino Perez who embarked on a mission to bring a world-class player into the club every year.
This campaign saw players like Zinedine Zidane, Ronaldo Nazario, Luis Figo, David Beckham, Robinho, and Michael Owen join already established players like Raul Gonzalez, Iker Casillas, and Roberto Carlos but despite their firepower, Real Madrid found success difficult to come by on the field and went trophyless between 2004 and 2007.
After the disbandment of the first 'galactico' era, a second one was begun in 2009 led by Cristiano Ronaldo and after initial setbacks, the long-awaited 'La Decima' was finally won in 2014.
This kickstarted an era of dominance by Real Madrid on the continent unprecedented in the modern era and the club became the first side to successfully defend the revamped Champions League trophy in 2017 and went one further by making it three in a row in 2018.
In addition to the aforementioned stars of the distant past, new superstars like Sergio Ramos, Gareth Bale, Karim Benzema, Marcelo, Toni Kroos, and Luka Modric have helped the club maintain their status at the pinnacle of world football.