Hearths Data Pack Wiki & Guide
wiki.9minecraft.net/hearths-9minecraft-data-pack/
The new Nether structures Hearths adds - crimson and warped towers and spirals - plus its natural decorations.
Overview
Hearths is a world-generation addition that fills the Nether with new structures and natural decorations, giving the dimension far more to find and explore. It scatters brand-new landmarks and ambient features across the Nether's biomes so travelling through it feels like a real journey with places to discover. Because it is data-driven world generation, its content appears automatically in newly generated Nether chunks - you do not have to craft or set anything up.