To my understanding, Bangkok Stonehenge (real name being Hopewell Construction) was once a development project that began in 1990. The plan was to construct an elevated train system to take people to the airport. However, the funding was cut in 1992 and since then, these large pillars remain, overtaken by foliage and graffiti.
I gained interest in visiting this 'Stonehenge' when a fellow photographer mentioned to me these pillars will soon be torn down in order to make way for construction to begin over again. This easy trip cost about 23 baht in total (< one US dollar) and didn't take up much time.
So, you're interested in taking this trip because my descriptive words and beautiful imagery have convinced you?! Wow, that means a lot. If you do want to visit, start off at the Hua Lamphong Train Station which is connected directly to the Hua Lamphong MRT station. The train station is ornate and smells of cat urine. This combination is both confusing and concerning.