Lots of possibilities, and discussed in these forums lots of times in recent years... more commonly referred to as remote video source.
"Access" is not the right word to use in terms of common usage. The remote site is not 'accessing' anything. The remote site is one of many video sources (ie senders of video feed), and your challenge is routing that remote video feed, usually over open internet (with all the best effort, no guaranteed delivery of packets that goes with that). Depending on cameras, budget, ISP links in each location, etc... will factor into what might be a 'best' approach
as qhobbes said... as long as it fits within your requirements
another, typically much more sophisticated, secure, & pricier, option would be NDI bridge.
What you use will depend in part on budget, local system capabilities, requirements (including reliability, consistency), technical sophistication of operators in each location, etc.