Abstract: In the past few years, holography has served as a powerful tool in describing strong gravitational phenomena. Recently, several works have started to apply these tools to Big Bang-Big Crunch cosmologies. In this talk, I will describe the explicit construction of holographic 4D braneworld cosmologies and 4D eternally traversable wormholes by embedding End of the World (ETW) branes in 5D magnetically charged spacetimes. The two Lorentzian setups are derived from the same Euclidean saddle of the gravitational path integral in which the ETW brane takes the form of a Maldacena-Maoz wormhole. I will describe the features of these bulk setups and the properties of their holographic dual theories.