Hi!
those who are visting tirupati can make this trip to gudimallam about 31 Km from tirupati. it has an anicient shiva temple with a unique Linga. sofar archealogits are unableto find similar shiv linga anywhere in india. it is being worshipped even today. to reach one has to go through tirupati -renigunta-yerpedu-srikalahasti-naidupet route and take turn at yerpedu.
this shivlinga is said to be of satavahana time( 2nd century BC)
here is the link Indian Temples and Iconography: Gudimallam linga - Satavahana style
even srikalahasti temple is one of the most beatiful temples achitecture wise in south india.this is also a shiv temple. here it is called vayu lingam meaning air
both the temples are on the banks of swarnamukhi river