The unity, solidarity, and global reputation of the EU are in jeopardy due to various factors such as Greece's debt, Russia's involvement in Ukraine, Britain's desire to alter its relationship with the bloc, and migration in the Mediterranean. Failing to address any of these issues adequately would worsen the situation, increasing the dangers facing the EU. The immediate threat is Greece's potential default and the possibility of leaving the shared euro currency, known as 'Grexit', which challenges the concept of a closer union among European states and people. According to analysts Fabian Zuleeg and Janis Emmanouilidis from the European Policy Centre think-tank, the long-term effects of Grexit would have a significant impact on the EU as a whole, setting a precedent and further weakening the EU's fundamental purpose. Even though Greece only makes up a small portion of the euro zone's economy and population, its bankruptcy following two bailouts totaling nearly 200 billion euros is a significant blow to the EU's reputation. The atmosphere in Brussels was tense even before the results of the Greek referendum were revealed, with various groups pointing fingers and offering different explanations for the crisis. Despite the uncertainty surrounding Greece's future, it has already demonstrated that the idea of an unbreakable eurozone is flawed. Some partners may now try to strengthen ties among remaining members to prevent similar crises in the future, but opposition from Germany may hinder efforts to issue joint government bonds. The Greek situation will serve as a cautionary tale for markets in the event of future economic challenges within the euro zone. Destabilizing Greece's economy could worsen all three of Europe's other crises and unsettle the fragile southern Balkans, in addition to causing suffering and financial losses for European taxpayers. With existing tension in the eastern Mediterranean due to various conflicts and disputes, a collapsed Greece might seek assistance from Russia and potentially disrupt EU sanctions against Moscow. The influx of refugees from other conflicts is already straining Greece's resources, as authorities are eager for them to move on to seek asylum in other EU countries. It is easy to envision a scenario where a government kicked out of the euro zone leverages migrants to increase pressure on EU countries. The controversial "boat people" crisis has created rifts within the EU, with Italy and other frontline nations criticizing their northern and eastern counterparts for lack of solidarity in sharing the burden of refugees. Britain has also declined to participate. The failure to find a resolution to Greece's debt crisis after five years has weakened the EU's image in the eyes of global leaders such as Russian President Vladimir Putin and Chinese President Xi Jinping. Brussels officials admit that the euro zone crisis has led to a resurgence of national decision-making and diminished the influence of Europe's model of rules-based supranational governance. The EU's position in global trade and climate change negotiations has been undermined by Brexit, and there are concerns that it may face further challenges. Britain's plans to renegotiate its membership terms and hold a referendum by 2017 could result in the EU losing a significant economy, financial center, and military power. Despite polls indicating majority support for remaining in the EU and relief that Prime Minister David Cameron's renegotiation agenda is realistic, there is anxiety in Brussels following the unpredicted outcome of the May general election in the UK. After winning the election, Cameron has faced opposition from Eurosceptic members of his Conservative party. The ongoing Greek economic crisis, whether it remains in the euro zone or not, could support the argument that the UK is too closely tied to a failing system. Russia's historical animosity towards Britain, as seen in Moscow viewing the UK as a staunch ally of the US, would likely be pleased by the possibility of the UK leaving the EU. This could undermine efforts within the EU to confront Russian aggression in Ukraine and Georgia, as well as weaken the relationship between the UK and the EU, while still maintaining membership in NATO. This situation could give Putin an advantage in negotiations with German Chancellor Angela Merkel, who has been instrumental in European efforts to stabilize Ukraine. Rem Korteweg from the Centre for European Reform draws a comparison between the current crises facing the EU and the four horsemen of the apocalypse from the Book of Revelation. He describes these crises as representing conquest, war, famine, and death, and warns that EU leaders will struggle to control them. Korteweg emphasizes the need for a unified European response to prevent further chaos, instability, and conflict within the EU.