Delta Park is an lovely inner city park in Johannesburg. If you're short on time and just want to get some fresh air, this is where I'd go. As a bonus, dogs are allowed too!
Spanning an impressive 108 hectares, the park offers plenty of lush green grassland and wooded areas for you to explore. You can find three tree-lined dams, walking trails and bird hides. This is usually where I go after work to just walk and be in nature.
It also houses the Florence Bloom Bird Sanctuary and Delta Environmental Centre, where you can take part in wildlife-related courses and holiday programmes.
Enjoy it!