Middle ages gave way to religious world travels known as the Pilgrimage. People travel to get this religious satisfaction till the date. 2 million Muslims travel to Saudi Arabia to fulfill the religious obligation called Hajj from all across the world. The other big religious gathering occurs in Hinduism at the Kumbh Mela, where Hindus travel to bathe in the Holy River. The Christian travel to Rome; Jews to Jerusalem; Sikhs to the Golden Temple Amritsar. This a huge percentage of world travel comprises the Religious Pilgrimage.
17th Century gave birth to a new type of travel: The Grand Tour. This was supposed to be the rite of passage for the young men, designed to educate them after completion of formal education.
Again, this form of travel was initially availed by the rich. But the invention of Railways with cheaper fares opened the door for the middle class too.
Another reason for world travel is a business trip. It is not new. In ancient times the people used to travel for the resources i.e. the economic reasons.
Then the small scale trade tours started even before the industrial revolution. Nowadays there are thousands of multinational corporations and their directors and CEO make frequent visits to every country.
Leisure World Travel/ Tourism
The basic difference between travel and tourism is that tourism is travel without purpose. While the other travels are made with different aims, tourism is just for fun. The Roman Empire again a pioneer to establish world’s first resort.