For those looking for dark locations to visit, travel company My Late Deals has compiled a guide to some of the most popular destinations.
1. National 9/11 Memorial & Museum
This museum is a memorial created as a tribute of remembrance and honour to the 2,977 people who lost their lives in the terror attacks of 11 September 2001. Tickets to the museum can be purchased up to six months in advance.
Photo: National 9/11 Memorial & Museum
2. Memorial and Museum Auschwitz-Birkenau
This is the largest former German Nazi concentration and extermination camp. Over 1.1 million men, women and children lost their lives here. Entry to the museum is free, but entry cards should be reserved on the website
Photo: Memorial and Museum Auschwitz-Birkenau
3. Hiroshima Peace Memorial Museum
On 6 August 1954, downtown Hiroshima was devastated by an atomic bomb, making it the first city in the world to be attacked by an A-bomb. Admission costs 200 yen (roughly £1.57). Selfie sticks and large bags are not permitted.
Photo: Hiroshima Peace Memorial Museum
Radiation is still a problem in Chernobyl, but levels have lowered enough that the Ukrainian government allows visitors if they are with a tour guide and follow the rules. Banned clothing includes shorts, skirts and open footwear.