A civil union is a legally recognized partnership between two individuals that provides many of the same rights and responsibilities as marriage. Civil unions were created to offer legal protections and benefits to couples, particularly same-sex couples, before same-sex marriage became widely legalized. While civil unions grant rights such as inheritance, health care decisions, and tax benefits, they may not be recognized in all jurisdictions. This can lead to complications, especially when couples move to areas where only marriage is recognized, highlighting the differences between civil unions and marriage.