The 10 Most Valuable Classic Cars Sold at AuctionThe 10 Most Valuable Classic Cars Sold at Auction

With wacky investments such as jewelry, antique furniture or art, you don’t always know what you’re getting or whether the investment is going to pay off. Classic cars, however, may be the least risky wacky investment; they deliver the best returns compared with other luxury investments. For example, for the 12 months leading up to the first quarter of 2016, classic cars returned 17 percent, according to data by Knight Frank. They returned 161 percent over the five years ending in the first quarter of 2016.

It’s more than just a hobby. But should your clients invest? If the cars in these slides are any indication, you may not want to dismiss the idea.

Here, we rank the most valuable classic cars ever sold at auction, based on data gathered by MoneySuperMarket.com, a U.K.-based price-comparison website. The data was sourced from a Knight Frank report.