Kelvedon Hatch Secret Nuclear Bunker
Hidden (but recently signposted) underneath a fake farm house in Brentwood, England.
 
The bunker has served three functions during its lifespan, but the most recent and most interesting was as a standby government HQ in the event of a nuclear war.
 
The bunker was decommissioned in the 1980's but is available for general admittance.
 
Information on the not so secret bunker can be found here:
Hunterian Museum
The Hunterian Museum is a tribute to brothers John and William Hunter and can be found inside the Royal College of Surgeons in London.
 
The museum is filled with creepy medical specimens in jars, belonging to both animals and humans and also demonstrates some early forms of plastic surgery.
 
The most peculiar specimens include the skeleton of a giant (an eight foot man) and the skeleton of a scoliosis sufferer.
 
The museum is free to enter and open to the general public, although mainly used by medical students hoping to learn of the brothers practises.
 
Details of the museum can be found here:
 
The Door To Hell
The 'door to hell' opened up in Darvaza, Turkmenistan.
 
The fiery pit also known as the 'Darvaza Crater', measures 69 meters wide and 30 meters deep and has been burning for 40 years (since 1971).
 
The origin on the flaming hole is disputed. One theory is that Soviet engineers bored a hole in the area, and then set it alight when they believed it was emitting poisonous gas. The reult was the 'door to hell'.
 
Finding a local tour guide is advised whilst searching for this attraction, although it is accessible by 4 wheeled drive vehicale at the owner's risk.

Information about crater as well as travelling in Turkmenistan can be found here:
The Solent Forts
The Solent Forts are a set of four armoured forts that were built to protect the town of Portsmouth, England from seaborne attack.
 
The forts were built pre World War I and continued to be used until the end of World War II. They were eventually decommissioned in 1960.
 
Although 'St Helen's Fort' remains unoccupied, two of the other Forts; 'Spitbank' and 'No Man's Land' have been turned into luxury hotels, often putting on big parties and featuring such luxuries as swimming pools and even their own 'lazer battle'.
 
Horse Sand Fort has been preserved as a museum and is available to visit by boat.
 
For information on visiting the forts see:
Alnwick Poison Gardens
Alnwick gardens can be found on the site of Alnwick castle, England.
 
The castle is home to the Duke and Duchess of Northumberland, who decided to add a rather eerie feature to the 14 acres of land that accompany it.
 
The Duchess who reportedly once said ; 'I wondered why so many gardens around the world focused on the healing power of plants rather than their ability to kill.' decided to set up her very own 'poison gardens'.
 
The gardens contain over 100 noxious types of flora, from strychnine to hemlock, and are used as an educational means to teach people, in the Duchesses words;  'how a plant killed, how long it would take you to die if you ate it and how gruesome and painful the death might be.'
 
The gardens also have special permission from the home office to grow various forms of cannabis and magic mushrooms.
 
Information on visiting the poison garden can be found here:
Kryziu Kalnas
Kryziu Kalnas or the 'hill of crosses', sits roughly 7.5 miles north of Šiauliai, Lithuania.
 
Crosses started being placed on the hill in place of a former hill fort, as a sign of respect to those lost during the rebellian against Russian authorities in 1831 and 1863. The site was used to pray for peace for their country.
 
The site continued to be used until Lithuania was occupied by the Soviet union in 1944, who had the site bulldozed three times.

The spirit of the Lithuanian people could not be crushed however, and to this day people still add crosses to the site, which held an estimated 100,000 crosses at its last count in 2006.

Information on how to visit the hill of crosses can be found here:
Maunsell Sea Forts
The Maunsell sea forts can be found in the Thames and Mersey esturies in the United Kingdom.
 
They were built in 1942 in order to prevent the German Luftwaffe from penetrating the Uk's naval infrastructure.  After World War II the forts had outlived their usefullness and were decomissioned.
 
During the 1960's the Maunsell sea forts (named after their creator Guy Maunsell) were inhabited by pirate radio stations, who would illegally play music which would be picked up by radios across the UK.
 
One of the forts was seized from its former radio DJ inhabitants in 1967 by a man named Paddy Roy Bates and is now known as the principality of sealand
 
Boat trips around the forts are available from:
Object 825 GTS
Object 825 GTS was a top secret submarine base used during the cold war.  It can be found in Balaklava, in the disputed territory of Crimea, Ukraine.
 
The function of this top secret site was for the USSR to service/repair submarines, as well as to house submarines for retaliatory strikes against the US.
 
The site had heavily camouflaged entrances and housed ammunition, which at times included nuclear weapons (which were stored at a constant 15 degrees).
 
The site itself could house personnel in order to protect them from nuclear fallout.
 
The base was guarded until 1993, and was handed over to the armed forces of Ukraine, who turned it into a Naval Museum Complex.
 
Boat tours as well as walking tours of the base are possible. Information on how to take a tour can be found at:
Tagansky Protected Command Point
The Tagansky Protected Command Point also known as An-02, FS-572 or Bunker 42 is located near the underground station of Taganskaya 65 metres below Moscow, Russia.
 
The facility was built in 1956 as a command post headquarters for long-range aviation communications.
 
In the 1960's the bunker was upgraded to facilitate a nuclear attack. Two artesian wells were installed to provide clean, renewable drinking water and stocks of fuel and food were stored in preparation.
 
Tagansky Protected Command Point fell into disrepair in the 1970's and was officially declassified in 1995. The site was privately bought in 2006 and has now been converted into an entertainment complex featuring a cold war museum.
 
Tours of the 600 meter long network of tunnels are available from:
 
Plokstine Missile Base
The Plokstine Missile base is located near Ploksciai village in Plokstine Forest in Samogitia, Lithuania.
 
The base was quietly constructed in 1960 in Žemaitija National Park. It consists of a network of undergroud tunnels linking 4 concrete silos which were used to house missiles. 4 concrete domes above ground, would move on rails in the even of a missile launch.
 
The missiles held in the base were R-12 Dvina missiles with nuclear warheads which luckily, were never fired as the site had the ability to reach virtually every country in Europe.
 
An electric fence surrounded the site in order to keep people out which had the ability to raise its voltage to 1700V in the event of a security breach.
 
Since the missile base's decommissioning after the collapse of the Soviet Union, the base has been turned into a cold war museum and allows visitors into one of the four missile silos.
 
Tours of the site run from its associated visitor's centre. More information can be found at:
Subclub
Subclub is a subterranean night club situated in Bratislava, Slovakia.
 
The club was once an emergency military storage bunker built into the hill below Bratislava castle.
 
The bunker is entered from the base of the hill, through one of the long concrete tunnels linking it to other storage facilities and the outside world. The door at the entrance to the bunker is made from thick steel.
 
The club is mainly renowned for its drum and bass nights, although it also hosts techno, minimal, electro, ska and crossover club nights.
 
Check out event listings and line-ups on the club's official site:
Mirny Diamond Mine
Mirny Diamond Mine is an open pit diamond mine located in Mirny, Eastern Siberia, Russia.
 
The mine is the 2nd largest excavated hole in the world, measuring a diameter of 1200 meters and a depth of 525 meters.
 
Diamonds were discovered at the site in 1955 which led to the excavation process which started in 1957.
 
The location of the mine made the excavation incredibly difficult. The 7 month long Siberian winters made the ground hard to penetrate and the extreme weather conditions were even known to burst the tyres of vehicles working in the mine. 
 
The surface of the mine was closed in 2001 and filled in, in order to allow further mining to continue underground. The underground mines were closed in 2004.  The mine still remains a gaping hole in the ground.
 
Tours to the mine are available from:
Glass Beach
Glass Beach can be found near Fort Bragg in California, USA.
 
The once normal beach lies just South of an area used as a dump site between 1949 and 1967. 
 
In 1967 the California State Water Resources Control Board closed the dump and various clean up programmes were carried out in order to restore the area.
 
The metal from the dump was removed and over the following decades everything that was able to biodegrade, did.  Eventually all that was left was glass at the dump site.
 
The glass was eventually turned into what is known as 'sea glass'. The constant battery from the waves and sand of the beach rounded all of the edges of the broken glass and made it smooth. The glass now has the appearance of shiny colourful pebbles.
 
Two neighbouring beaches were also contaminated with the glass shards, which are accessible from the same road that leads to Glass Beach.
 
'California State Parks' offer more information on the beach at: