Many tourists come because of Nessie alone. Other than the loch, there is also the Nessie Pub, a popular pub near the loch; and the Nessie Tours company, which specializes in submarine and rowboat tours into the loch, for customers who are hoping to see Nessie. Apparently, people are allowed to swim in the loch as well.
The loch was the original site for a Sherlock Holmes movie featuring the Loch Ness Monster, which was actually a submarine prop. However, filming was stopped when the prop sprung a leak and sunk, and the movie was never made.