Globular clusters are ancient objects that formed ~10 billion years ago. The oldest globular clusters can be as old as ~13 billion years. As a result, globular clusters have a low abundance of heavy elements such as iron and silicon that are necessary for the formation of rocky worlds like the Earth. Nevertheless, data from NASA’s Kepler space telescope has shown that rocky planets can readily form around stars with abundances of heavy elements as low as those found in globular clusters.
It turns out that globular clusters might be the perfect place for advanced civilisations to inhabit. The small distances between stars means that interstellar communication between stars is expected to take only days, weeks, or months. For comparison, a signal sent from Earth to Alpha Centauri, the nearest star system, would take over 4 years. An advanced civilisation in a globular cluster that has the same level of technology as the one currently on Earth would have already known a great deal about the nearest ~100,000 stars. Most of the planets around these stars would have already been detected and even characterised. Sending exploratory probes to these planets would be much easier since signals sent from the home planet takes take only days, weeks, or months to reach them.
However, planets in globular clusters can have their orbits disrupted by close encounters with passing stars. This is due to the dense stellar environments of globular clusters. Fortunately, globular clusters are ancient objects and so they only contain low-mass stars as more massive stars have shorter lifespans. The majority of stars in globular clusters are expected to be low-mass red dwarf stars.
Because the luminosities of stars drop steeply with decreasing mass, the habitable zone around low-mass stars is expected to be much closer-in than Earth is from the Sun. This means that planets orbiting within the habitable zone of stars in globular clusters are sufficiently close-in that their orbits are unlikely to be disrupted due to interactions with passing stars. Basically, the more compact a planetary system is, the less likely it will be disrupted by passing stars.
Given that the stars in a globular cluster are billions of years older than the Sun, an advanced civilisation residing in a globular cluster could be far older than the one on Earth and could have already colonised the entire cluster. An advanced civilisation with colonies around many different stars would be immune to many existential threats. If an apocalyptic event occurs on one planet, the civilisation would still continue on other worlds. Finally, the view from the surface of a rocky planet in a globular cluster would be breathtaking. The entire night sky would be densely packed with stars.
Stefano & Ray (2016), “Globular Clusters as Cradles of Life and Advanced Civilizations”, arXiv:1601.03455 [astro-ph.EP]