We present recent results from numerical simulations performed with
the TREE+SPH code Gadget-2. We implemented a complete self-consistent
model for chemical evolution that allows us to simulate the chemical
enrichment evolution of the cosmic structure. We divide the talk in two 
parts; In the first part, we compare the simulated and observed 
properties of galaxy clusters focusing on the unresolved issues. In the 
second part we present the results from an unprecedented simulation of 
the high-redshift universe (z>2.5) including the formation of 
extremely metal-poor stars (PopIII).