The City of Newisle map was created for Minecraft for Android by only one person. Gradually, it grew in MCPE to such a size that it looks completely immodest. Now it has more than 500 different buildings in the MCPE. And if you go down to Minecraft BE underground, you can ride the subway.
And this can be done in Minecraft Bedrock Edition for a very long time. After all, the metro system already consists of 12 branches! And if you go up to the roof of the tallest building that the City of Newisle map offers, you can see the edge of the map – the textures will be in fog.