This dormant volcano in Tanzania is called Mount Kilimanjaro and is known to be highest mountain in Africa. Don't confuse walking or trekking with climbing, and don't underestimate this mountain. Climbing the Kilimanjaro is considered quite hard and difficult. You should have experience before trying this mountain and also well prepared in both mental as physical. Your local travel agent can advice you and also judge if you are ready for such a great achievement or better to wait and start with smaller ones first.
When thinking of California most will think of beaches, dune buggies or even the tech industry in Silicon Valley. But California contains so much more interesting places like for instance the mountain El Capitan. While it's possible to climb it's also possible to hike this mountain on certain routes with the right help of your local travel agent. A fun fact, climbers are required by law to carry a so called 'poop tube' to avoid polluting the mountain.
Almost every climber has seen that movie 127 hours with James Franco about a rock climber who got stuck and had to make a difficult decision. When seeing that movie, we all know the importance of carrying the right equipment. For every type of mountaineering experience a different additional set of solid equipment is required. But for the general rock climbing gear it's advised to have of course rope, a harness, a belay device and very importantly good & strong shoes. It's not a requirement but both beginners as well experienced climbers should wear helmets.