Most sex clubs cater to the swinging lifestyle. Most major cities in North America and western Europe have sex clubs, many in a permanent location, but they often keep a low profile. Thousands of swinging clubs are listed on various adult websites and swinger social networks, but there are believed to be many other small neighborhood clubs, which are known among members of the lifestyle community, without a website. The rules of these clubs vary considerably, and admissions are not necessarily limited to married couples.