You're back in London - and the rain has stopped! This is your reward for finding all of the secrets in the game. If you notched them all, you can save your game when the Meteorite Cavern is behind you and load up All Hallows from there. It also comes up automatically after the game credits have rolled. Though there are several cool things to do, this is just for fun.
As you slide into the level, be sure to jump and roll to finish the slide backwards. Grab the edge as you exit the slide and let go and grab again to find a crevice. Shimmy a long way left and pull up into a crawlspace. Drop down the other side and move forward to climb a block and find a spiked hallway round to the right. Jump forward and grab the gratings on the roof. Monkey swing over the spikes and pick up the Save Crystal and flares at the end. Return to the crawlspace and safety drop to the ground outside.
From ground level, check out the metal walkways up above. You can get onto the lowest one from a concrete block on the other side of the lead domed roof (near the entrance slide). Take a running jump from the first walkway to the L-shaped one in the corner and from there a running jump and grab will get you to the next.
A final running jump takes you to the walkway attached to the central concrete pillar. Remember that route - you'll be repeating it... Clamber to the slightly higher walkway on your left and then take a standing jump to the sloping section of the platform ahead of you. Walk up the slope to the edge of the flat section and jump straight up and grab the edge of the platform above your head. Haul up, turn left and repeat the manouevre to reach some Uzi clips.
Return to the ledge with the sloping section using safety drops. Walk one step onto the sloping section and take a standing jump forward to grab the monkey bars underneath the platform above. Swing forward over the railings in front of you and drop onto a concrete ledge, scaring up a few harmless bats as you land. From the centre of the ledge, do a standing jump/grab to reach the crawlspace where the bats were hiding. Pull up and pickup the small medikit.
Crawl forward and you'll find a pit containing a Save Crystal. Return to the entrance and safety drop to the ground (it's a long way, but ignore the damage if you're short on medikits). Climb back up to the walkway attached to the central pillar the same way as before. This time go to the right end of the raised section and grab the edge of the sloping platform in front of you. Haul up and run and jump up the slope to the ledge with some flares.
Check your health at this point and then take a running jump from the flares to the right hand pillar of the two you can see in front of you. From the highest side of this pillar, grab the monkey bars above you and either monkey-swing about a meter and drop, or monkey swing to near the end and drop, slide, grab and drop again. Either way you're on a dodgy bit of roof and Lara crashes through the it into a church. Lara just barely survives the fall if she has full health. Luckily, there's a large medikit on the landing.
Take a running jump to the purple canopy and collect the flares. Turn left and check out the walkway beneath the single stained glass window. Near you is a section that sticks out. Angle LAra towards that section, hop back from the edge and take a standing jump. Grab the Uzi clips and large medikit from the pit nearby and then jump over to the black and white tiled walkway. Up above you is an alcove with a switch. Throw it and return to the ledge.
Climb down to the the small tiled section below the ledge and take a running jump to grab the edge of the tiled section on the right side of the central construction. Haul up and climb onto the sloping ledge to your right. Look across the way to see a crevice. You can grab it with a standing jump from the sloping ledge, angled slightly to the left. Shimmy left until you can pull up.
Pick up the large medikit and throw the switch in the alcove. A dim hallway opens at ground level. Turn around and have a look around. Theres a suspended platform a little way away that you could probably jump to if the roof wasn't so low directly in front of you. Take an angled jump out of the alcove into thin air on the left and bend around to the right in mid air to land (hopefully!) on the platform. Take another running jump to the tiled ledge ahead to pick up a small medikit.
Return to the previous suspended platform and safety drop to ground level. Head anti clockwaise around the room to find the door you just opened. Run across the collapsing flooring. Throw the switch at the end of the hall. Monkey-swing above the spikes back to the main room. Near the central construction is a suspended ledge you can grab by jumping and pull yourself onto. From here climb up upto the ledge at head height and turn around. Take a running jump back to the black and white tiled ledge.
Jump forward from this ledge to grab the ceiling grates. Head to the left. Drop and grab from the end of the monkey swing, and pull up into the small area. Climb up past the rope slider. Collect the vault key and climb back down to take a trip on the rope swing. When Lara passes the second stained glass window, it's about time to let go. From the ledge where Lara lands, grab the nearby pillar and pull up into the small space.
Hang off the other side of the pillar, and a door opens. Follow the passage and hang drop to a metal ledge in a corridor filled with spikes. Pick up the small medikit. The funny things in the centre of this corridor catch fire easily and you'll have to swing down one of the sides for safety. You'll likely catch fire at the end anyway, so when you hear a clanking noise let go of the swing, drop into a pool of water and check your health.
Time your swim past the piston. Climb out and head for the crawlspace at the end of the alcove. Crawl through and push the button. On the upper ledge to the right as you face the button is a small medikit. Return through the crawlspace and climb the gratings in the nearby alcove.
Up above the ladder, walk a step forward and roll and grab the ledge to defeat the trapdoor. From the same spot, take a standing jump over the gap and grab the edge. Continue on into the main area. Climb up the column at the end of the ledge and drop a long way down into a pool of oily water. Climb out into a dark vaulted room.
Check out the alcoves and shoot out the grating in the one on the far left for a packet of flares. You can do the same to the grating in the middle alcove but there's nothing there and all the switch does is open a difficult route back to the main area - which you shouldn't need to take if you switched the alcove switch shortly after falling through the roof...
Use the key to open the vault and grab the large medikit in one corner. Drop into the water hole at the other end of the room to find yourself in the vaults under the church. From the look of it there were prisoners down here when it flooded!
Swim forward halfway along the vault and take a right. Go right again and swim to the end to pick up a Save Crystal from an alcove on the left. Swim back into the main vault and go to the far end to exit - straight into a reception committee! Clear the area without going too close to the burning drum and then locate the climbable grating and climb up into the church, where there's a pile of goodies to be collected...