Thanks to its global appeal, club football is a lucrative business. There is a lot of money involved when it comes to football at the highest levels. Extravagant spending and costly mistakes are all part of the game. But when the risks do pay off, the clubs and their brands grow, which then leads to more opportunities for expansion.Football clubs have been given a major reality check by Covid-19. With matchday revenue plummeting to unforeseen levels, clubs had to work out elaborate plans to manage their finances. Even then, not many clubs have managed the financial crisis caused by the pandemic well enough to come out of it unscathed.This summer's transfer window has been an extraordinary one. We've seen plenty of high-profile deals go over the line and if you look at the numbers closely, you can see a power shift gradually taking place.Without further ado, let's take a look at five of the most valuable clubs in the world.(Numbers courtesy: Transfermarkt)#5 Liverpool - €880 millionLiverpool v Crystal Palace - Premier LeagueLiverpool have had some wonderful seasons in recent times under Jurgen Klopp. The German coach led them to the UEFA Champions League title in the 2018-19 season. The Merseysiders then won their first league title of the Premier League era in the 2019-20 season.However, Liverpool had a rather forgettable outing in the 2020-21 season. They were hit hard by long-term injuries to players like Virgil van Dijk, Joel Matip, Jordan Henderson and Joe Gomez, among a few others.Liverpool's reliable front three are arguably not as good as they used to be a couple of seasons ago. Salah is still at it but Mane and Firmino have struggled to find form. They haven't invested heavily in the summer either. Ibrahima Konate was their only signing of the summer and he arrived on a deal worth €40 million.Liverpool still hold more titles than Man United 👀 pic.twitter.com/TgfCWhKHzx— ESPN FC (@ESPNFC) May 26, 2021#4 Chelsea - €882 millionManchester City v Chelsea FC - UEFA Champions League FinalChelsea's fortunes have changed drastically since January. The Blues had invested heavily in the summer of 2020. They brought in a lot of quality personnel. Players like Kai Havertz, Timo Werner, Ben Chilwell, Hakim Ziyech and Edouard Mendy were all signed up.Even though most players did not hit the ground running, the team became much more organized following the appointment of Thomas Tuchel. The Blues won the UEFA Champions League in the 2020-21 season.They signed Romelu Lukaku from Inter Milan on a deal worth a club-reco €115 million this summer. They've also added Saul Niguez to their midfield on a loan deal and now have one of the strongest and deepest squads in Europe.Kai Havertz joined @ChelseaFC #OnThisDay last year 🇩🇪Has he scored any important goals since then? We can't remember 😉 pic.twitter.com/E94gssbzYr— Premier League (@premierleague) September 4, 2021