If you find yourself in Lima, Peru, you must experience Los Olleros downhill. 11,500 feet of downhill ending at the Pacific Ocean. The challenges are many and the views are vast. One of the top Bucket List rides of all time.
This is a full-day adventure with a multi-hour bus shuttle up to the start of the trail. The first section of trail is hard pack, then sandy, and then sandy with rocks. After the steeper sections let off, you ride along a dry river canyon out to the ocean. The dry river bed has some fun narrow and technical riding in it, so be sure to not just blow by everything. Take your time, enjoy the views and the experience!
There are several guide services that offer tours of Peru, and by all means you should take advantage of these companies. They offer a safer way to experience Peru and just a fraction of its culture and scenery.
Check out Sacred Rides for their Peru All-Mountain adventure, they did an excellent job.