Beginning April 2018 the conservative country of Saudi Arabia is now opening up to Westerners in a big way by beginning to issue tourist visas. Foreigners have long been able to enter the country for religious, business and personal visits in the past, but this is the first time the kingdom issues visa specifically for tourism purposes.
Details are still emerging, but you still need to work with a registered tour operator and have a minimum of four guests traveling. Those who's passports contain evidence of travel to Israel may also be refused admission, so be sure to obtain a second temporary passport prior to any visa applications.
Women over 25 are now allowed to visit Saudi Arabia on their own, but will still need to wear a headscarf/completely cover up and most likely will have to remain with a group.