The highest degree in Freemasonry is the third degree; that's it. However, further learning in Masonry is still available to the Master Mason. A Master Mason is given a set of keys to many new doors that were previously unavailable to him. A brother can choose to go the Scottish Rite or York Rite path, as well as the OES route, the Shrine route or a myriad of other groups.
Scottish Rite is a series of 29 degrees numbered 4° to 32°. Each degree teaches moral and philosophical lesson to the brothers going through them. The degree work is done very differently than in a Lodge as each are presented as one act plays and the brothers sit in the audience. Scottish Rites are divided into Valleys and most states don't have more than a handful of Valleys. This means that the classes are much larger than you would find in other bodies in Masonry. Chapter and Council work are done in a more traditional way.
Royal Arch Chapters are local just like Lodges. Corinthian Chapter #33 meets in the same building as my Lodge and I know many members. I was a single candidate, making the experience very personal. I hadn't been a candidate for almost 4 years so this experience brought back many great memories of my first time in Lodge. In fact, that is the greatest quality of the York Rite. The degrees are conferrred one at a time with a brother as the candidate, taking a part in the action. Chapter is not passive but an active process of learning and studying. I participated in the first degree of a Chapter known as the Mark Master degree.
I won't reveal the actual ceremony but I will quote what the General Grand Chapter has to say about the degree:
The Mark Master Degree is believed to have originated as a ceremony of registering a craftsman's mark in those years distinguished by operative craft masons and their temple building. It was later developed into a full-fledged degree by the Masonic fraternity as we know it today, Some scholars say it was the earliest degree and may predate all others by many years. It is highly regarded by students in all Masonry, teaching lessons that have proven of value in all walks of life. Some Grand Lodges place so high an eminence on the Mark Master Degree, that they confine it to the jurisdiction of a separate grand body, the Grand Lodge of Mark Masters.
I really liked the personal experience within a Royal Arch Chapter. The work performed by the brothers really felt special because I was the only candidate. Taking part in lessons helps to impress them on my mind more completely. I was truly impressed by the work of the brothers and I really feel that I have increased my knowledge in Masonry. And as I carry this penny with me, I will continue to improve myself in Masonry and in life.