I did some digging because I was curious. From the Horn, you'd go north through Egypt and Israel. From there, to get to Turkey (and then Greece), the close ro

I did some digging because I was curious. From the Horn, you'd go north through Egypt and Israel. From there, to get to Turkey (and then Greece), the close route would go through Syria. Not a great choice given the civil war. You can swing around Syria, but it takes you farther from Greece. If you still wanted to get to Greece, you'd have to cross through Turkey and get across the border to Greece, who has installed fences (and probably other impediments). Once in Greece, they do deport, so that's always a risk. Stepping back, once you go around Syria, you're fairly close to Russia (much closer than Greece). It's also a longer and harder to secure border (the Turkey-Greece border is very, very narrow). Get into Russia, swing to the east to avoid the Ukrainian war, skip past Belarus, Estonia and Latvia because of existing refugee issues and Finland is the next stop. I think the EU must have that border locked down, because the wikipedia page for the Belarus-EU border crisis shows refugees from Istanbul getting to Belarus via Russia. The TLDR is that getting into the EU via Russia appears to be a significant route. I'm guessing due to border lockdowns in southern EU countries.