Wat Saket Ratchawora Mahawihan, also known as Wat Saket or the Golden Mount Temple was originally built during the Ayutthaya era, then renovated by several kings and was even once used as a cremation ground during a cholera outbreak. The highlight of the temple is the golden mount hill with a chedi on top that offers panoramic views of the city.
It's a perfect place to watch the SUNSET (and probably sunrise :)). There's a charming garden around the hill temple where when we visited also hosted a fair. To enter the temple grounds is free but to climb to the top costs 100 thb.
It's 300 steps to the top and there's bells you can ring on the way to the top that can get quite loud but the experience is fun. You'll notice how you hear the bells even from afar just by walking nearby to the temple!