From Philipp Lahm to Giorgio Chiellini and Dante, there is an abundance of big names to choose from while judging the best defenders in the Champions League.
Over the following slides, we pick just 10 defenders to watch out for in Europe this season.
It can't be easy.
The following players have been selected according to their current form and appearances in Europe over the last season. This is not an all-time list, so former greats or players who are arguably past their best have not been included.
Is there anyone you think should have made the top 10? Let us know who and why in the comments section below!
There is a golden generation of footballers coming out of Belgium at the moment, one of whom is former Ajax defender Toby Alderweireld.
Perhaps not a household name in England, until he was linked with Liverpool, Arsenal and Tottenham Hotspur over the summer, Alderweireld put in some consistently impressive performances in Holland over the last four years.
The central defender has won three straight Eredivisie titles with Ajax and has played for Belgium at every level from U15 to the senior squad.
Having signed for Atletico Madrid over the summer, Alderweireld has joined a side that has won two Europa Leagues in the last five years. This season's Champions League draw has been kind to the Spanish side, who join Porto, FC Zenit St Petersburg and Austria Vienna in Group G.
Atletico would be one of the favorites to progress beyond the group stage and Alderweireld is one to watch at the tournament progresses.
Known for his strength and ability on the ball, Squawka.com describes the 24-year-old as: "A talented ball-playing defender, schooled in the technique and execution of passing from his nine years at Ajax."
The Belgian's partner in central defence will be Diego Godin, an experienced Uruguayan international who has been at the Vicente Calderon since 2010.
Manchester City's millions have not helped them mount a serious Champions League campaign. Yet. The last two seasons have been disappointing for the Citizens, who have failed to advance beyond the group stage of the European competition.
But this term, things are different. Manuel Pellegrini is at the helm and they have a raft of exciting new players, experienced both in Europe and international football. Perhaps this could be their year to advance to the latter stages of the tournament.
City share Group D with Bayern Munich, CSKA Moscow and Viktoria Plzen. It won't be a walk in the park but, as Malaga showed last season, Pellegrini knows how to operate in Europe.
One player worth keeping tabs on is Matija Nastastic. Signed by City in August 2012, the centre-back has all the hallmarks of a star for the future.
Raphael Varane will be one of Europe's top defenders for many years to come.
The 20-year-old central defender has been likened to Laurent Blanc, by none other than Zinedine Zidane. He exudes confidence, doesn't seem to be fazed by anything and has one of the coolest heads in the Real Madrid back-line.
Varane made 11 Champions League appearances last season and had 15 La Liga games, managing to unseat Pepe to partner Sergio Ramos in defence.
At 6'3" the Frenchman cuts an imposing figure; he is quick, agile, assured and also scores goals. In fact, when making his El Clasico debut, Varane became an instant hero to Madridistas when he scored against Barcelona in the first leg of the Copa del Rey.
The young defender also scored in the second leg at the Camp Nou, stealing the headlines from Ronaldo and Messi.
He may not be the finished article just yet, but Varane is an exciting talent for now and for the future of the Champions League.
It took no time for Jordi Alba to establish himself as one of the best full-backs in Europe when he signed for Barcelona in 2012.
Originally a product of La Masia, Alba had spent most of his senior career with Valencia before returning to Camp Nou.
He impressed during Euro 2012, starting six times for a Spain side that went on to win the tournament and scoring in the 4-0 final win against Italy.
It's Alba's ability to both defend and attack that makes him such a good asset for Barcelona and Spain.
His speed, tireless energy and ability to press forward down the left flank makes him great to watch. Technically first-rate, Alba is also good in the air, despite his small stature. At just 24, there is still a lot more to come from the Spaniard.
Alba will be key this season for Barcelona in Group H. Barca have been drawn against AC Milan, Ajax and Celtic, by no means an easy group.
It's hard to believe that Bayern Munich left-back David Alaba is only 21-years-old.
The Austrian, who started playing in Bayern's youth system in 2008, has the composure and self-confidence of a player far beyond his years.
In his second full campaign at the club, Alaba won the Champions League, the Bundesliga and the DFB Pokal.
During Jupp Heynckes' treble-winning season, Alaba made 11 appearances in the Champions League, winning nine games, drawing one and losing one.
Alaba also registered two goals and two assists during Bayern's road to the European final at Wembley.
The two-time Austrian footballer of the year is versatile and athletic. His athleticism is used to devastating effect for Bayern—the speed at which he can burst forward to attack is one of his best attributes yet he is as good in defence as he is going forward.
Borussia Dortmund centre-back Mats Hummels may be guilty of making an occasional error but that should not detract from the fact that he is currently one of the best defenders in Europe.
It should not be forgotten that it was Hummels' late goal against Shakhtar Donetsk that saw Dortmund force a 2-2 draw in the Champions League round of 16 last season.
The 24-year-old is one game away from his 200th appearance for Borussia Dortmund. In the last four years he has won two Bundesliga titles, the DFB Pokal and the DFL Supercup.
The German international came up through the youth ranks at Bayern Munich, before making a switch to the Westfalenstadion in 2009. He's a classic, no-nonsense centre-half who is good in the air, tough-tackling but also happy to venture forward, showing off his dribbling skills and able to pull off the odd killer pass.
There are some areas to improve, in terms of concentration and his occasional poor positioning, but it's merely a footnote on an otherwise flawless CV.
Juventus' Giorgio Chiellini is up there with the best central defenders in the world right now.
The 29-year-old Italian was unfortunate to have his season hampered by injury in 2012/13, but he still played a pivotal role for his side in Serie A and the Champions League.
The Old Lady's defensive record has been immense in recent seasons—in 2011/12 they went unbeaten in the Serie A, last term they kept 19 clean sheets and in the Champions League they enjoyed a run of five consecutive shut-outs before exiting at the hands of Bayern Munich.
Chiellini has profited greatly from the addition of Andrea Barzagli and Leonardo Bonucci to the squad, with the three manning a defence that has become one of the strongest in Europe over the last couple of seasons.
The Italian's never-say-die attitude is what most people love about him, he doesn't give up, he throws himself into tackles and he is completely and utterly uncompromising.
The kind of defender anyone would love to have on their team, Chiellini is always one to watch out for.
Group B will be defined by the battles between Real Madrid and Juventus. Real Madrid have one of the best attacking teams in Europe and Juve have one of the most formidable back lines.
Antonio Conte's three-man defence consists of a trio of world-class defenders, Barzagli, Chiellini and Bonucci.
In 2012/13, Barzagli started 34 Serie A games for Conte's side and played a massive role in Juve winning their second Scudetto in as many years—keeping 19 clean sheets along the way.
In the Champions League last season, Juve managed to keep five clean sheets in a row as they swept past the likes of FC Nordsjaelland, Chelsea, Shakhtar Donetsk and Celtic.
This season they will be a dominant force again in Europe and could even be dark horses to win the competition.
Barzagli edges out Chiellini in my opinion for his composure, perfectly-timed tackles, strength and sheer determination. This is a player who was signed from Wolfsburg in 2011 for £264,000 and has gone on to establish himself as one of the standout defenders in Serie A.
If you aren't familiar with Barzagli's game, watch as Gareth Bale, Cristiano Ronaldo, Isco and co attempt to run rings around Juventus in this season's Champions League. Chances are, you won't forget him.
One of the bargains of recent years has to be Dante's €4.7 million move from Borussia Monchengladbach to Bayern Munich.
The Brazilian defender had quite the first season at his new club—winning the Champions League, the DFB Pokal and the Bundesliga, with a resounding lead of 25 points.
No-one expected him to be that good, especially in his initial days at the club, but he exceeded all expectations.
His performances for the Bundesliga club also got him his first call-up to the Selecao, and he went on to win the 2013 Confederations Cup over the summer.
The 29-year-old is everything you would want from a centre-half—strong, physical, good in the air, calm and composed.
As with the best Brazilian defenders, Dante also weighs in with the occasional goal; he scored eight while at Monchengladbach and has registered one so far in him time at the Allianz Arena. He also scored this goal against Italy at the Confederations Cup.
An incredible statistic from last season is the fact that Bayern conceded just 18 goals over the course of the Bundesliga season. Dante's rock-like solidity in central defence played a huge part in this feat.
When Pep Guardiola describes you as "the cleverest player he has ever worked with," you can assume you're doing a pretty stellar job.
This is exactly what the Bayern Munich manager said of Philipp Lahm, following his side's UEFA Super Cup win against Chelsea last month.
Quoted on Goal.com, Guardiola said:"Lahm is perhaps the most intelligent player I have ever trained in my career. He is at another level."
The 29-year-old's honours make for impressive reading: Lahm can count five Bundesliga titles, a Champions League win and five DFB Pokals among his collection.
One of the best full-backs in the world, Lahm is a natural leader who captains both club and country.
Paris Saint-Germain and Brazil defender Thiago Silva is the best defender in world football at the moment.
He has already added a Ligue 1 winner's medal to his honours—helping the side to their first domestic league win since 1994.
An impressive summer spent captaining Brazil in the Confederations Cup ended with Barcelona engaged in a relentless pursuit for the 28-year-old.
Silva's rock-solid performances against the La Liga side in the Champions League last season are worth watching time and time again.
It was indicative of how highly he is rated by PSG that, when Barcelona came calling, they increased his wages to €12 million a year to ensure he stayed at the club, as reported by ESPNfc.com.
In the Champions League, to the 2014 World Cup and beyond, Thiago Silva is always one to watch.